Miniaturized impedance sensors for wearable devices

ABSTRACT

A method, system, apparatus, and/or device for measuring a physiological condition of a user. The method, system, apparatus, and/or device may include: a band configured to attach to a body part of a user; a housing coupled to the band; a processing device integrated into the band or disposed within the housing; an interface integrated into the band or disposed within the housing; and a miniaturized impedance sensor.

BACKGROUND

Electronic technologies may take advantage of micro- and nanoscalephysical properties and interactions to perform functions of electronicdevices. Nanoelectronics specifically take advantage of the molecularcomposition of materials and the structural properties of materials atthe nanoscale. Such structures may include thin films and/or nanotubes.Thin films generally comprise materials layered in single- tomulti-atom-thick sheets. Thin films may be used in optical applications,electrical applications, and/or may be used as a protective layer.Nanotubes may generally include materials formed into tubes with single-to multi-atom-thick walls. Nanotubes may be used in electricalapplications as conductors, and/or may be used to provide nanoscalestructural support.

BRIEF DESCRIPTION OF THE DRAWINGS

The present description will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousembodiments of the present embodiment, which description is not to betaken to limit the present embodiment to the specific embodiments butare for explanation and understanding. Throughout the description thedrawings may be referred to as drawings, figures, and/or FIGs.

FIG. 1 illustrates a perspective view of a wearable device, according toan embodiment.

FIG. 2A illustrates a top exposed view of the wearable device in FIG. 1, according to an embodiment.

FIG. 2B illustrates a profile view of the wearable device, according toan embodiment.

FIG. 2C illustrates a side view of the wearable device, according to anembodiment.

FIG. 3A illustrates the wearable device attached to a part of a body ofan individual, according to an embodiment.

FIG. 3B illustrates the wearable device with the second sensor beinglocated approximate the first muscular-walled tube and the light sourceand the first sensor being located approximate the secondmuscular-walled tube, according to an embodiment.

FIG. 3C illustrates the wearable device with the second sensor beinglocated approximate the second muscular-walled tube and the light sourceand the first sensor being located approximate the first muscular-walledtube, according to an embodiment.

FIG. 3D illustrates the wearable device with the light source, the firstsensor, and the second sensor being located longitudinally andapproximate the first muscular-walled tube, according to an embodiment.

FIG. 3E illustrates the wearable device with the light source, the firstsensor, and the second sensor being located laterally and approximatethe first muscular-walled tube, according to an embodiment.

FIG. 3F illustrates the wearable device with the light source, the firstsensor, and the second sensor being located in parallel and approximatethe first muscular-walled tube, according to an embodiment.

FIG. 3G illustrates the wearable device with the light source and thefirst sensor being located approximate the first muscular-walled tubeand the second sensor being located approximate the secondmuscular-walled tube, according to an embodiment.

FIG. 3H illustrates the wearable device with the light source and thefirst sensor being located approximate the second muscular-walled tubeand the second sensor being located approximate the firstmuscular-walled tube, according to an embodiment.

FIG. 3I illustrates a sensor array for aligning the first sensor, thelight source, and/or the second sensor with the muscular-walled tube,according to an embodiment.

FIG. 4A illustrates a perspective view of a miniaturized impedancesensor with an interstitial filler distributed between miniaturizedelectrodes, according to an embodiment.

FIG. 4B illustrates a head-on view of a first side of the miniaturizedimpedance sensor illustrated in FIG. 4A, according to an embodiment.

FIG. 4C illustrates a head-on view of a second side of the miniaturizedimpedance sensor illustrated in FIG. 4A, according to an embodiment.

FIG. 5A illustrates a perspective view of the miniaturized impedancesensor with an interstitial filler disposed between miniaturizedelectrodes in a row, according to an embodiment.

FIG. 5B illustrates a head-on view of a first side of the miniaturizedimpedance sensor illustrated in FIG. 5A, according to an embodiment.

FIG. 5C illustrates a head-on view of a second side of the miniaturizedimpedance sensor illustrated in FIG. 5A, according to an embodiment.

FIG. 6 illustrates a perspective view of the miniaturized impedancesensor with an interstitial filler disposed between rows of miniaturizedelectrodes, according to an embodiment.

FIG. 7A illustrates a side view of the miniaturized impedance sensorwith circular miniaturized electrodes, according to an embodiment.

FIG. 7B illustrates a perspective view of the miniaturized impedancesensor of FIG. 7A, according to an embodiment.

FIG. 8 illustrates a partially exploded schematic view of theminiaturized impedance sensor electrically coupled to a circuit board,according to an embodiment

FIG. 9 illustrates a partially exploded schematic view of theminiaturized impedance sensor, according to an embodiment.

FIG. 10 illustrates a partially exploded schematic view of aminiaturized impedance sensor with an insulating column betweenneighboring miniaturized electrodes, according to an embodiment.

FIG. 11A is a picture of a miniaturized electrode for use in aminiaturized impedance sensor, according to an embodiment.

FIG. 11B is a picture of a nanotube forest within the miniaturizedelectrode of FIG. 11A, according to an embodiment.

FIG. 11C is a picture of various configurations of rows of miniaturizedelectrodes, according to an embodiment.

FIG. 11D is a picture of miniaturized electrode pillars, according to anembodiment.

FIG. 11E is a picture of miniaturized electrode strips, according to anembodiment.

FIG. 12A illustrates a schematic view of a section of the wearabledevice with an integrated sensor, according to an embodiment.

FIG. 12B illustrates a zoomed in view of the integrated sensorillustrated in FIG. 12A, according to an embodiment.

FIG. 13A illustrates the wearable device on a wrist of a user, accordingto an embodiment.

FIG. 13B illustrates the wearable device on an arm of a user, accordingto an embodiment.

FIG. 14A illustrates impedance paths for the miniaturized impedancesensor from a side view of the miniaturized impedance sensor, accordingto an embodiment.

FIG. 14B illustrates the impedance paths for the miniaturized impedancesensor of FIG. 14A from a perspective view of the miniaturized impedancesensor, according to an embodiment.

FIG. 15A illustrates impedance paths through various subcutaneous layersof a user of a wearable device, where the wearable device is alignedperpendicular to a muscular-walled tube, according to an embodiment.

FIG. 15B illustrates the impedance paths through the subcutaneous layersillustrated in FIG. 15A, where the wearable device is aligned parallelto the muscular-walled tube, according to an embodiment.

FIG. 16A illustrates a graph showing electric field lines betweenelectrodes of the miniaturized impedance sensor at a first separationdistance, according to an embodiment.

FIG. 16B illustrates a graph showing electric field lines betweenelectrodes of the miniaturized impedance sensor at a second toseparation distance, according to an embodiment.

FIG. 17A illustrates miniaturized electrodes against skin of a useraligned parallel to a muscular-walled tube, according to an embodiment.

FIG. 17B illustrates miniaturized electrodes against skin of a useraligned perpendicular to a muscular walled tube, according to anembodiment.

FIG. 17C illustrates an electronic schematic of the miniaturizedelectrodes described regarding FIGS. 17A-B, according to an embodiment.

FIG. 17D illustrates interdigitated miniaturized electrodes, accordingto an embodiment.

FIG. 17E illustrates sets of miniaturized electrodes with interdigitatedfingers, according to an embodiment.

FIG. 17F illustrates interdigitated miniaturized electrodes betweenelectrode pads, according to an embodiment.

FIG. 18 illustrates a controls schematic for the miniaturized impedancesensor, according to an embodiment.

FIG. 19 illustrates a heartbeat waveform as measured by the miniaturizedimpedance sensor, according to an embodiment.

FIG. 20A illustrates a method of preparing the miniaturized impedancesensor, according to an embodiment.

FIG. 20B illustrates a method of placing miniaturized electrodes on adevice substrate, according to an embodiment.

FIG. 21 illustrates a method of preparing the nano impedance similar tothe method illustrated in FIG. 20 , including a single step fordepositing multiple layers, according to an embodiment.

FIG. 22 illustrates a method for preparing the miniaturized impedancesensor with polymeric nano structures, according to an embodiment.

FIG. 23 illustrates a method for three-dimensional printing of theminiaturized impedance sensor, according to an embodiment.

FIG. 24 illustrates a block diagram of electronic components of awearable device, according to an embodiment.

FIG. 25 illustrates a wearable device in communication with a computingdevice, according to one embodiment.

FIG. 26 illustrates a block diagram of an electronic device with acorrelator, a baseliner, and an alerter, according to an embodiment.

DETAILED DESCRIPTION

Miniaturized impedance sensors as disclosed herein will become betterunderstood through a review of the following detailed description inconjunction with the figures. The detailed description and figuresprovide merely examples of the various embodiments described herein.Those skilled in the art will understand that the disclosed examples maybe varied, modified, and altered and not depart from the scope of theembodiments described herein. Many variations are contemplated fordifferent applications and design considerations; however, for the sakeof brevity, the contemplated variations may not be individuallydescribed in the following detailed description.

Throughout the following detailed description, example embodiments ofvarious miniaturized impedance sensors are provided. Related elements inthe example embodiments may be identical, similar, or dissimilar indifferent examples. For the sake of brevity, related elements may not beredundantly explained in multiple examples. Instead, the use of a same,similar, and/or related element names and/or reference characters maycue the reader that an element with a given name and/or associatedreference character may be similar to another related element with thesame, similar, and/or related element name and/or reference character inan example embodiment explained elsewhere herein. Elements specific to agiven example may be described regarding that particular exampleembodiment. A person having ordinary skill in the art will understandthat a given element need not be the same and/or similar to the specificportrayal of a related element in any given figure or example embodimentin order to share features of the related element.

As used herein “may” should be interpreted in the permissive sense andshould not be interpreted in the indefinite senses. Use of “is”regarding embodiments, elements, and/or features should be interpretedto be definite only regarding a specific embodiment and should not beinterpreted as definite regarding the invention as a whole. Referencesto “the disclosure” and/or “this disclosure” refer to the entirety ofthe writings of this document and the entirety of the accompanyingillustrations, which extends to all the writings of each subsection ofthis document, including the Title, Background, Brief description of theDrawings, Detailed Description, Claims, and Abstract. Terms such as“configured to,” “operable to,” “designed to,” “positioned to,” “alignedto,” and so forth indicate a purposeful design feature as opposed to ahappenstance structural capability.

Where multiples of a particular element are shown in a FIG., and whereit is clear that the element is duplicated throughout the FIG., only onelabel may be provided for the element, despite multiple instances of theelement being present in the FIG. Accordingly, other instances in theFIG. of the element having identical or similar structure and/orfunction may not have been redundantly labeled. A person having ordinaryskill in the art will recognize based on the disclosure herein redundantand/or duplicated elements of the same FIG. Despite this, redundantlabeling may be included where helpful in clarifying the structure ofthe depicted example embodiments.

A conventional wearable device may include a means of attaching thedevice to a user and one or more measurement devices. Such conventionaldevices may include devices such as a step counter, a smart watch, aFitbit™, an Apple™ watch, a Samsung™ watch, and so forth. Currently, theamount and type of data collected from an individual wearing a wearabledevice may be limited by the space available in a wearable for sensors,communications chips, processors, power sources, the accuracy of sensorscapable of being integrated into a wearable device, the size of thesensors, and/or the materials used for the sensors. Previous sensorshave been too large to fit on a user comfortably in a wearable and/orhave not been accurate enough to provide meaningful data. A specificexample regards conventional bioimpedance sensors. A conventionalbioimpedance sensor may include two impedance pads. A particularphysiological condition that may be measured by a conventionalbioimpedance sensor may depend on the size of each impedance padrelative to the current delivered from one impedance pad to the otherand/or the separation distance between the impedance pads. Accordingly,the practicality of implementing a conventional bioimpedance sensor on awearable device may be limited by the minimum size of the impedance padsand the ways in which wearing such device may be tolerable to a user.

A further limiting factor of conventional bioimpedance sensors may bethe amount and time of contact the impedance pads have with skin of auser. The presence of water, such as sweat, on the skin may affect themeasurement, as may the surface area of the impedance pad contacting theskin at the time the measurement is taken. In order to maximize theaccuracy of a measurement taken, the amount of surface area contactbetween the skin of a user and the impedance pads may be optimized. Thepresent inventors have discovered that there may be an “acclimationperiod” over which the skin against which a bioimpedance sensor may beplaced tends to conform to the bioimpedance sensor shape. If thewearable is jostled or moved on the user, this may restart theacclimation period. Thus, in addition to minimizing the movability ofthe wearable on the user, minimizing the acclimation may improvemeasurement accuracy.

Implementations of embodiments described and/or illustrated throughoutthis disclosure may address the above-mentioned deficiencies byproviding methods, systems, devices, and/or apparatuses that mayincorporate miniaturized impedance sensors. In one embodiment, aminiaturized impedance sensor may include a miniaturized impedancesensor. The miniaturized impedance sensor may include miniaturizedelectrodes on a flexible substrate. The miniaturized impedance sensormay be integrated into a flexible and/or durable wearable device. Anadvantage of the miniaturized impedance sensor may be improved contactbetween the sensor and a user wearing the wearable device. Anotheradvantage of the miniaturized impedance sensor is that a large number ofelectrodes may be incorporated into the sensor over a relatively smallarea, allowing for a variety of measurement depths using a singlesensor. Yet another advantage of the miniaturized impedance sensor maybe durability against traumas such as strikes, bending, drops, and soforth. Yet another advantage of the miniaturized impedance sensor may bedrastic reduction and/or elimination of the acclimation period.

FIG. 1 illustrates a wearable device 100 with integrated sensors 112and/or 114, according to an embodiment. The elements and/or featuresdescribed regarding FIG. 1 may be the same as and/or similar to othersimilarly named elements and/or features described and/or illustratedthroughout this disclosure. In one embodiment, the wearable device 100may be configured to take physiological measurements of a user. Thewearable device 100 may include a housing 118 and an attachmentmechanism 106, such as a band, that are configured or shaped to attachto a body of the user. In one embodiment, the wearable device 100 may bea wrist worn device that may be configured to attach to a wrist or armof the user. In one example, the integrated sensors 112 and/or 114 maybe positioned against an inside region of the wrist when the user wearsthe wearable device 100. The inside region of the wrist may face towardsthe user in a natural resting position. In another example, when theintegrated sensors 112 and/or 114 may be positioned against an insideregion of the body part, such as the wrist, the integrated sensors 112and/or 114 may be positioned adjacent to, approximate to, or directlyover a muscular-walled tube that is closest to an outer surface of thebody part. In another embodiment, the wearable device 100 may beattached to a head of the user using a headband, to a chest of the userusing a chest band, to an ankle of the user using an ankle band, orotherwise attached to a body of the user using a sweatband, bandage,band, watch, bracelet, ring, adherent, or other attachments andconnections.

In various embodiments, the housing 118 may be moveably coupled to theband 106. In one example, the band 106 may be a flexible band designedto flex into a curvilinear shape. The flexible band with a shape, size,and/or flexibility designed for attaching the band 106 to a wrist of auser. The wrist may include a dermal layer along an underside of thewrist and a muscular-walled tube within the wrist adjacent to the dermallayer along the underside of the wrist. The housing 118 may beconfigured with external electrical contacts. The band 106 may beconfigured with multiple contact points or a continuous contact strip.The housing 118 may be coupled to the band 106 such that the externalelectrical contacts of the housing 118 form electrical contact with theone or more of the multiple contact points or the continuous contactstrip of the band 106. The housing 118 may be moved on the band 106 to adifferent position and still maintain electrical communication withelectrical components embedded in the band 106 such as the electricaltrace or circuit 116, the first sensor 112, or the second sensor 114.

The wearable device 100 may include a processing device 102, a userinterface or display device 104, the band 106, a power source 108, aprocessing unit 110, the first sensor 112, and/or the second sensor 114.In one embodiment, the processing device 102, the user interface ordisplay device 104, the power source 108, the processing unit 110, thefirst sensor 112, and/or the second sensor 114 may be electronicallycoupled and/or communicatively coupled. In another embodiment, theprocessing device 102 and the display device 104 may be integrated intothe housing 118 of the wearable device 100. In another embodiment, thepower source 108, the processing unit 110, the first sensor 112, and/orthe second sensor 114 may be integrated into the band 106 of thewearable device 100. In one embodiment, the first sensor 112 and/or thesecond sensor 114 may be integrated or positioned along an insidesurface or interior surface of the band 106, such that the first sensor112 and/or the second sensor 114 may be flush with the surface of theband 106 to contact a body part of a user when worn or protrude from asurface of the band 106 to extend toward a surface of the body part ofthe user when worn. In another embodiment, the band 106 may include acavity that the power source 108, the processing unit 110, the firstsensor 112, and/or the second sensor 114 may be stored in. In anotherembodiment, the band 106 may be formed or molded over the power source108, the processing unit 110, the first sensor 112, and/or the secondsensor 114. In another embodiment, the power source 108, the firstsensor 112, and/or the second sensor 114 may be connected to theprocessing unit 110 and/or the processing device 102 by one or moreelectrical trace(s) or circuit(s) 116 (such as flexible circuit boards).

In one embodiment, the first sensor 112 may be a miniaturizedspectrometer. The miniaturized spectrometer may include acarbon-nanotube structure forming a collimator, an optical filter, and aphotodetector stacked together and embedded in the band 106. Thephotodetector may be positioned in the band 106 to face the user's bodypart 320 when the user wears the band 106. In another embodiment, thesecond sensor 114 may be a miniaturized impedance sensor. In anotherembodiment, the first sensor 112 and/or the second sensor may be atemperature sensor, a viscosity sensor, an ultrasonic sensor, a humiditysensor, a heart rate sensor, a dietary intake sensor, anelectrocardiogram (EKG) sensor, an ECG sensor, a galvanic skin responsesensor, a pulse oximeter, an optical sensor, and so forth. In anotherembodiment, the wearable device 100 may include other sensors integratedor attached to the band 106 or the housing 118. In another embodiment,the wearable device 100 may be communicatively coupled to the wearabledevice 100, such as sensors of other devices or third-party devices.

The first sensor 112 and/or the second sensor 114 may be coupled to theprocessing unit 110. The processing unit 110 may be configured to manageor control the first sensor 112, the second sensor 114, and/or the powersource 108. In one embodiment, the processing unit 110 may control afrequency or rate over time that the first sensor 112 and/or the secondsensor 114 take measurements, a wavelength or optical frequency at whichthe first sensor 112 and/or the second sensor 114 take measurements, apower consumption level of the first sensor 112 and/or the second sensor114, a sleep mode of the first sensor 112 and/or the second sensor 114and so forth. In another embodiment, the processing unit 110 may controlor adjust measurements taken by the first sensor 112 and/or the secondsensor 114 take measurements to remove noise, increase a signal to noiseratio, dynamically adjust the amount of measurements taken over time,and so forth.

In another embodiment, the power source 108 may be coupled to theprocessing unit 110. The power source 108 may be a battery, a solarpanel, a kinetic energy device, a heat converter power device, awireless power receiver, and so forth. The processing unit 110 may beconfigured to transfer power from the power source 108 to the processingdevice 102, the display device 104, the first sensor 112, the secondsensor 114, and/or other devices or units of the wearable device 100. Inone embodiment, the processing unit 110 may be configured to regulate anamount of power provided from the power source 108 to the processingdevice 102, the display device 104, the first sensor 112, the secondsensor 114, and/or other devices or units of the wearable device 100. Inanother embodiment, the wearable device 100 may include a power receiverto receive power to recharge the power source 108. For example, thepower receiver may be a wireless power coil, a universal serial bus(USB) connector, a thunderbolt connector, a mini USB connector, a microUSB connector, a USB-C connector, and so forth. The power receiver maybe coupled to the processing unit 110, the processing device 102, thepower source 108, and so forth. In one embodiment, the processing unit110 may be configured to regulate an amount of power provided from thepower receiver to the power source 108. In another embodiment, theprocessing unit 110 may be a power management unit configured to controlbattery management, voltage regulation, charging functions, directcurrent (DC) to DC conversion, voltage scaling, power conversion,dynamic frequency scaling, pulse-frequency modulation (PFM), pulse-widthmodulation (PWM), amplification, and so forth. In another embodiment,the processing unit 110 may include a communication device configured tosend and/or receive data via a cellular communication channel, awireless communication channel, a Bluetooth® communication channel, aradio communication channel, a WiFi® communication channel, and soforth.

The processing device 102 may include a processor, a data storagedevice, a communication device, a graphics processor, and so forth. Inone embodiment, the processing device 102 may be coupled to theprocessing unit 110, the power source 108, the first sensor 112, and/orthe second sensor 114. In one embodiment, the processing device 102 maybe configured to receive measurement data from the processing unit 110,the first sensor 112, and/or the second sensor 114. In one embodiment,the processing device 102 may be configured to process the measurementdata and display information associated with the measurement data at thedisplay device 104. In another embodiment, the processing device 102 maybe configured to communicate the measurement data to another device. Inone embodiment, the other device may process the measurement data andprovide information associated with the measurement data to the user oranother individual. In another embodiment, the other device may processthe measurement data and provide results, analytic information,instructions, and/or notifications to the processing device 102 toprovide to the user. The wearable device 100 may communicate informationassociated with the measurement data or information related to themeasurement data to a user via the display device 104, a buzzer, avibrator, a speaker, a microphone, and so forth. In one example, thedisplay device 104 may include an input device, such as a button, atouch screen, a touch display, an so forth that may receive an inputform the user.

In another embodiment, the wearable device 100 may be part of a systemconnected to other devices. For example, the wearable device 100 may beconfigured to send and/or receive data with another device. In oneembodiment, the wearable device 100 may be configured to receive datafrom another measurement device, aggregate the received data withmeasurement data from the first sensor 112 and/or the second sensor 114,analyze the aggregated data, and provide information or notificationsassociated with the analyzed data.

FIGS. 2A-C illustrate side and top views of a wearable device 100,according to an embodiment. FIG. 2A illustrates a top exposed view ofthe wearable device 100 in FIG. 1 , according to an embodiment. Some ofthe features in FIG. 2A are the same as or similar to some of thefeatures in FIG. 1 as noted by same and/or similar reference characters,unless expressly described otherwise. Furthermore, the elements and/orfeatures described regarding FIG. 2A may be the same as and/or similarto other similarly named elements and/or features described and/orillustrated throughout this disclosure. As discussed above, the wearabledevice 100 may be a wrist-worn device that may be configured to attachto a wrist of a user. As further discussed above, the processing device102 and the display device 104 may be integrated into the housing 118 ofthe wearable device 100 and the power source 108, the processing unit110, the first sensor 112, and/or the second sensor 114 may beintegrated into the band 106 of the wearable device 100. In oneembodiment, the band 106 may include a cavity that the power source 108,the processing unit 110, the first sensor 112, and/or the second sensor114 may be stored in. In another embodiment, the band 106 may be formedor molded over the power source 108, the processing unit 110, the firstsensor 112, and/or the second sensor 114. In various embodiments, theband 106 may be formed of silicone and/or canvas material.

FIG. 2B illustrates a profile view of the wearable device 100, accordingto an embodiment. Some of the features in FIG. 2B are the same as orsimilar to some of the features in FIG. 1 and FIG. 2A as noted by sameand/or similar reference characters, unless expressly describedotherwise. Furthermore, the elements and/or features described regardingFIG. 2B may be the same as and/or similar to other similarly namedelements and/or features described and/or illustrated throughout thisdisclosure. In one embodiment, the housing 118 with the processingdevice 102 and the display device 104 (as shown in FIGS. 1 and 2A) maybe located at a top of the wearable device 100 such that the housing 118may be located at a top surface of a wrist of a user when the user wearsthe wearable device 100 on their wrist. In another embodiment, the firstsensor 112 and/or the second sensor 114 (as shown in FIGS. 1 and 2A) maybe located at a bottom of the wearable device 100 such that the firstsensor 112 and/or the second sensor 114 may be located at a bottomsurface of a wrist of a user when the user wears the wearable device 100on their wrist. In another embodiment, the power source 108 and/or theprocessing unit 110 (as shown in FIGS. 1 and 2A) may be located along aside of the wearable device 100 such that the power source 108 and/orthe processing unit 110 may be located at a side surface of a wrist of auser when the user wears the wearable device 100 on their wrist.

FIG. 2C illustrates a side view of the wearable device 100, according toan embodiment. Some of the features in FIG. 2C are the same or similarto some of the features in FIGS. 1-2B as noted by same referencecharacters, unless expressly described otherwise. As discussed above,the wearable device 100 may include the power source 108, the processingunit 110, the first sensor 112, and/or the second sensor 114. In anotherembodiment, the power source 108, the first sensor 112, and/or thesecond sensor 114 may be connected to the processing unit 110 and/or theprocessing device 102 by one or more electrical trace(s) or circuit(s)116. In one embodiment, the electrical trace 116 may extend at leastpartially along a circumference of the band 106. In one embodiment, thepower source 108 may be located on one or both sides of the band 106,the first sensor 112 and/or the second sensor 114 may be located at abottom of the band, and the processing unit 110 may be located at a sideor a top of the band 106 (such as approximate the housing 118). In oneembodiment, the electrical trace(s) 116 may extend along a circumferenceof the band 106 along a side or middle circumference of the band 106.The electrical trace(s) 116 may transfer data and/or power between thepower source 108, the first sensor 112, the second sensor 114, theprocessing unit 110, the processing device 102 (as shown in FIG. 1 ),and/or the display device 104 (as shown in FIG. 1 ).

FIGS. 3A-H illustrate various embodiments of the wearable device 100positioned on a user relative to veins and/or arteries of the user,according to various embodiments. FIG. 3A illustrates the wearabledevice 100 attached to a part of a body 320 of an individual, accordingto an embodiment. Some of the features in FIG. 3A are the same as orsimilar to some of the features in FIGS. 1-2B as noted by same and/orsimilar reference characters, unless expressly described otherwise.Furthermore, the elements and/or features described regarding FIG. 3Amay be the same as and/or similar to other similarly named elementsand/or features described and/or illustrated throughout this disclosure.In one embodiment, the wearable device 100 may be attached to the partof the body 320 of the individual. The part of the body 320 may be anarm, a leg, a hand, a wrist, a head, an appendage, and so forth of thebody 320 of the individual. For example, the wearable device 100 may beattached to a wrist or arm of the body 320 of the individual. Asdiscussed above, the wearable device 100 may include the first sensor112 and/or the second sensor 114. In another embodiment, the firstsensor 112 and or the second sensor 114 may be attached to a band of thewearable device 100 such that the first sensor 112 and/or the secondsensor 114 may be aligned over a muscular-walled tube 322 and/or 324 ofthe body 320 of the individual. The muscular-walled tube 322 and/or 324may be a vein, an artery, or other tubes or channels to circulate fluidsin the body 320, such as blood, water, oxygen, and so forth. Forexample, the first muscular-walled tube 322 may be an ulnar artery orvein and the second muscular-walled tube 324 may be a radial artery orvein.

In one embodiment, the wearable device 100 may include one or more lightsources 326 integrated into the band of the wearable device 100 suchthat the light sources 326 are offset to a first side of the firstmuscular-walled tube 322 and extend horizontally along surface of theskin offset to the muscular-walled tube 322. The light source(s) 326 maybe light emitting diodes (LEDs), incandescent bulbs, tungsten bulbs,lasers, and so forth. In one embodiment, the wearable device 100 mayinclude the first sensor 112 integrated into the band of the wearabledevice 100 such that the first sensor 112 may be offset to a second sideof the muscular-walled tube 322 and extend horizontally along surface ofthe skin offset to the muscular-walled tube 322. In one embodiment, thelight sources 326 may be located at a first side of the muscular-walledtube 322 and the first sensor 112 may be located opposite to the lightsources 326 on the other side of the muscular-walled tube 322. Inanother embodiment, the second sensor 114 may be a miniaturizedimpedance sensor that may be positioned over top of the muscular-walledtube 322. The muscular-walled tube may include a blood vessel such as avein or artery in an arm or wrist of a body 320 of the user, such as ahuman body. In one embodiment, the second sensor 114 may be integratedinto the band of the wearable device 100 such that the second sensor 114may run parallel to and extend horizontally along surface of the skinabove the muscular-walled tube 322.

The first sensor 112 and the second sensor 114 may be compactly arrangedin the wearable device 100. The close proximity of the first sensor 112,the second sensor 114, and/or the light source 326 may reduce an amountof wiring disbursed throughout the wearable device 100. The first sensor112, the second sensor 114, and/or the light source 326 may beintegrated into and/or on a single substrate. The substrate may beflexible and/or rigid. Compact arrangement of the sensors may allow foruse of a rigid substrate, which may increase the durability of thesensors and/or the wearable device 100 overall. Compact arrangement ofthe sensor may also allow for consistency of measurement. In variousembodiments, such as embodiments discussed regarding FIG. 26 ,measurements of multiple sensors may be correlated and/or aggregated.Compact arrangement may allow for measurement by multiple sensors of thesame muscular-walled tube 322 at the same or roughly the same locationon the muscular-walled tube. This may increase the precision ofcorrelations and/or aggregations.

FIG. 3B illustrates the wearable device 100 with the second sensor 114being located approximate the first muscular-walled tube 322 and thelight source 326 and the first sensor 112 being located approximate thesecond muscular-walled tube 324, according to an embodiment. Some of thefeatures in FIG. 3B are the same as or similar to some of the featuresin FIGS. 1-3A as noted by same and/or similar reference characters,unless expressly described otherwise. Furthermore, the elements and/orfeatures described regarding FIG. 3B may be the same as and/or similarto other similarly named elements and/or features described and/orillustrated throughout this disclosure. In one embodiment, the secondsensor 114 may be located over the first muscular-walled tube 322. Inone embodiment, the second sensor 114 may include a miniaturizedimpedance sensor. In one embodiment, the first muscular-walled tube 322may extend along a Y-axis of a first plane and the miniaturizedimpedance sensor may extend perpendicularly relative to the firstmuscular-walled tube 322 along an X-axis of a second plane, such thatthe miniaturized impedance sensor extends from a first side of the firstmuscular-walled tube 322 to a second side of the first muscular-walledtube 322. In another embodiment, the first sensor 112 may be located ata first side of the second muscular-walled tube 324 and the lightsource(s) 326 may be located on a second side of the secondmuscular-walled tube 324, such that the first sensor 112 and the lightsource(s) 326 straddle each side of second muscular-walled tube 324.

FIG. 3C illustrates the wearable device 100 with the second sensor 114being located approximate the second muscular-walled tube 324 and thelight source 326 and the first sensor 112 being located approximate thefirst muscular-walled tube 322, according to an embodiment. Some of thefeatures in FIG. 3C are the same as or similar to some of the featuresin FIGS. 1-3B as noted by same and/or similar reference characters,unless expressly described otherwise. Furthermore, the elements and/orfeatures described regarding FIG. 3C may be the same as and/or similarto other similarly named elements and/or features described and/orillustrated throughout this disclosure. In one embodiment, the secondsensor 114 may be located over the second muscular-walled tube 324. Inone embodiment, the second sensor 114 may include a miniaturizedimpedance sensor. In one embodiment, the second muscular-walled tube 324may extend along a Y-axis of a first plane and the miniaturizedimpedance sensor may extend perpendicularly relative to the secondmuscular-walled tube 324 along an X-axis of a second plane, such thatthe miniaturized impedance sensor may extend from a first side of thesecond muscular-walled tube 324 to a second side of the secondmuscular-walled tube 324. In another embodiment, the first sensor 112may be located at a first side of the first muscular-walled tube 322 andthe light source(s) 326 may be located on a second side of the firstmuscular-walled tube 322, such that the first sensor 112 and the lightsource(s) 326 straddle each side of first muscular-walled tube 322.

The embodiments illustrated in FIGS. 3B-C generally illustrateembodiments where the first sensor 112 is placed to take measurementsnear and/or from one muscular-walled tube, and the second sensor 114 isplaced to take measurements near and/or from another muscular-walledtube. The two muscular-walled tubes may have different featurescorresponding to different physiological conditions, physiologicalparameters, and/or physiological constituents. The two muscular-walledtubes may have different features corresponding to a change in aphysiological condition, physiological parameter, and/or physiologicalconstituent. For example, one of the muscular-walled tubes may be avein, and the other muscular-walled tube may be an artery. In general,arteries may carry oxygenated blood, and veins may carry deoxygenatedblood. In the embodiments illustrated in FIGS. 3B-C, the arrangements ofthe sensor may allow for correlation of oxygenated blood to deoxygenatedblood. This in turn may inform a determination of a physiologicalcondition, physiological parameter, and/or physiological constituent ofa user of the wearable device 100. For example, the wearable device 100may include the processing unit 110, which may correlate measurementstaken by the first sensor 112 and the second sensor 114 placed over thefirst muscular-walled tube 322 and the second muscular-walled tube 324,respectively, to determine that the blood is not being sufficientlyoxygenated.

FIG. 3D illustrates the wearable device 100 with the light source 326,the first sensor 112, and the second sensor 114 being locatedlongitudinally and approximate the first muscular-walled tube 322,according to an embodiment. Some of the features in FIG. 3D are the sameas or similar to some of the features in FIGS. 1-3C as noted by sameand/or similar reference characters, unless expressly describedotherwise. Furthermore, the elements and/or features described regardingFIG. 3D may be the same as and/or similar to other similarly namedelements and/or features described and/or illustrated throughout thisdisclosure. In one embodiment, the first sensor 112 may be located at afirst side of a first location along the first muscular-walled tube 322and the light source(s) 326 may be located on a second side of the firstlocation along the first muscular-walled tube 322, such that the firstsensor 112 and the light source(s) 326 straddle each side of the firstlocation along the first muscular-walled tube 322. In anotherembodiment, the second sensor 114 may be located over a second locationalong the first muscular-walled tube 322. In another embodiment, thesecond sensor 114 may include a miniaturized impedance sensor. In oneembodiment, the first muscular-walled tube 322 may extend along a Y-axisof a first plane and the miniaturized impedance sensor may extendperpendicularly relative to the first muscular-walled tube 322 along anX-axis of a second plane, such that the miniaturized impedance sensormay extend from a first side of the first muscular-walled tube 322 to asecond side of the first muscular-walled tube 322. In one embodiment,the first location along the first muscular walled tube 322 may belocated above or ahead of the second location along the first muscularwalled tube 322 along the Y-axis. In another embodiment, the firstlocation along the first muscular walled tube 322 may be located belowor behind of the second location along the first muscular walled tube322 along the Y-axis.

FIGS. 3A-D generally show the second sensor 114 aligned with its lengthparallel to the length of the muscular-walled tubes. Parallel alignmentof the second sensor 114 to the muscular-walled tubes may allow formeasurements and/or characterization of features running parallel to thelength of the muscular-walled tubes. For example, in embodiments wherethe second sensor 114 includes the miniaturized impedance sensor, thecurrent passed into the user by the miniaturized impedance sensor mayrun parallel or roughly parallel to the length of the muscular-walledtube to which the miniaturized impedance sensor corresponds. In anembodiment where the muscular-walled tube includes a vein or artery,parallel alignment of the miniaturized impedance sensor may allow formeasurement and/or characterization of the blood in the vein or arteryalong a path of the blood in the vein or artery. Similarly, parallelalignment of the miniaturized impedance sensor may allow for measurementand/or characterization of the muscular-walled tube along the length ofthe muscular-walled tube.

FIG. 3E illustrates the wearable device 100 with the light source 326,the first sensor 112, and the second sensor 114 being located laterallyand approximate the first muscular-walled tube 322, according to anembodiment. Some of the features in FIG. 3E are the same as or similarto some of the features in FIGS. 1-3D as noted by same and/or similarreference characters, unless expressly described otherwise. Furthermore,the elements and/or features described regarding FIG. 3E may be the sameas and/or similar to other similarly named elements and/or featuresdescribed and/or illustrated throughout this disclosure. In oneembodiment, the first sensor 112 may be located at a first side of alocation along the first muscular-walled tube 322 and the lightsource(s) 326 may be located on a second side of the location along thefirst muscular-walled tube 322, such that the first sensor 112 and thelight source(s) 326 may straddle each side of the first location alongthe first muscular-walled tube 322. In another embodiment, the secondsensor 114 may be located over the same location along the firstmuscular-walled tube 322. In another embodiment, the second sensor 114may include a miniaturized impedance sensor. In one embodiment, thelight source 326, the first sensor 112, and the second sensor 114 mayextend laterally along the X-axis and perpendicularly to themuscular-walled tube 322. In one embodiment, the second sensor 114 maybe located between the light source 326 and the first sensor 112. Inanother embodiment, the second sensor 114 may be located at an exteriorside of the light source 326 or the first sensor 112. In anotherembodiment, a first portion of the second sensor 114 may be located atan exterior side of the light source 326 and a second portion of thesecond sensor 114 may be located at an exterior side of the first sensor112.

Perpendicular alignment of the second sensor 114 to the muscular-walledtubes may allow for measurements and/or characterization of featuresrunning perpendicular to the length of the muscular-walled tubes. Forexample, in embodiments where the second sensor 114 includes theminiaturized impedance sensor, the current passed into the user by theminiaturized impedance sensor may run perpendicular or roughlyperpendicular to the length of the muscular-walled tube to which theminiaturized impedance sensor corresponds. In an embodiment where themuscular-walled tube includes a vein or artery, perpendicular alignmentof the miniaturized impedance sensor may allow for measurement and/orcharacterization of a cross-sectional area of the blood in the vein orartery. Similarly, perpendicular alignment of the miniaturized impedancesensor may allow for measurement and/or characterization of themuscular-walled tube along the circumference and/or diameter of themuscular-walled tube.

FIG. 3F illustrates the wearable device 100 with the light source 326,the first sensor 112, and the second sensor 114 being located inparallel and approximate the first muscular-walled tube 322, accordingto an embodiment. Some of the features in FIG. 3F are the same as orsimilar to some of the features in FIGS. 1-3E as noted by same and/orsimilar reference characters, unless expressly described otherwise.Furthermore, the elements and/or features described regarding FIG. 3Fmay be the same as and/or similar to other similarly named elementsand/or features described and/or illustrated throughout this disclosure.In one embodiment, the first sensor 112 may be located at a first sideof a first location along the first muscular-walled tube 322 and thelight source(s) 326 may be located on a second side of the firstlocation along the first muscular-walled tube 322, such that the firstsensor 112 and the light source(s) 326 may straddle each side of thefirst location along the first muscular-walled tube 322. In anotherembodiment, the second sensor 114 may be located over a second locationalong the first muscular-walled tube 322. In another embodiment, thesecond sensor 114 may include a miniaturized impedance sensor. In oneembodiment, the first muscular-walled tube 322 may extend along a Y-axisof a first plane and the impedance pad(s) may extend parallel to thefirst muscular-walled tube 322 along a Y-axis of a second plane, suchthat the impedance pad(s) extend along a portion of the firstmuscular-walled tube 322. In one embodiment, the first location alongthe first muscular walled tube 322 may be located above or ahead of thesecond location along the first muscular walled tube 322 along theY-axis. In another embodiment, the first location along the firstmuscular walled tube 322 may be located below or behind of the secondlocation along the first muscular walled tube 322 along the Y-axis.

FIG. 3G illustrates the wearable device 100 with the light source 326and the first sensor 112 being located approximate the firstmuscular-walled tube 322 and the second sensor 114 being locatedapproximate the second muscular-walled tube 324, according to anembodiment. Some of the features in FIG. 3G are the same as or similarto some of the features in FIGS. 1-3F as noted by same and/or similarreference characters, unless expressly described otherwise. Furthermore,the elements and/or features described regarding FIG. 3G may be the sameas and/or similar to other similarly named elements and/or featuresdescribed and/or illustrated throughout this disclosure. In oneembodiment, the second sensor 114 may be located over the secondmuscular-walled tube 324. In one embodiment, the second sensor 114 mayinclude a miniaturized impedance sensor. In one embodiment, the secondmuscular-walled tube 324 may extend along a Y-axis of a first plane andthe miniaturized impedance sensor may extend parallel relative to thesecond muscular-walled tube 324 along a Y-axis of a second plane, suchthat the miniaturized impedance sensor may extend along a portion of thesecond muscular-walled tube 324. In another embodiment, the first sensor112 may be located at a first side of the first muscular-walled tube 322and the light source(s) 326 may be located on a second side of the firstmuscular-walled tube 322, such that the first sensor 112 and the lightsource(s) 326 may straddle each side of first muscular-walled tube 322.

FIG. 3H illustrates the wearable device 100 with the light source 326and the first sensor 112 being located approximate the secondmuscular-walled tube 324 and the second sensor 114 being locatedapproximate the first muscular-walled tube 322, according to anembodiment. Some of the features in FIG. 3H are the same as or similarto some of the features in FIGS. 1-3G as noted by same and/or similarreference characters, unless expressly described otherwise. Furthermore,the elements and/or features described regarding FIG. 3H may be the sameas and/or similar to other similarly named elements and/or featuresdescribed and/or illustrated throughout this disclosure. In oneembodiment, the second sensor 114 may be located over the firstmuscular-walled tube 322. In one embodiment, the second sensor 114 mayinclude a miniaturized impedance sensor. In one embodiment, the secondmuscular-walled tube 324 may extend along a Y-axis of a first plane andthe miniaturized impedance sensor may extend parallel relative to thefirst muscular-walled tube 322 along a Y-axis of a second plane, suchthat the miniaturized impedance sensor may extend along a portion of thesecond muscular-walled tube 324. In another embodiment, the first sensor112 may be located at a first side of the second muscular-walled tube324 and the light source(s) 326 may be located on a second side of thesecond muscular-walled tube 324, such that the first sensor 112 and thelight source(s) 326 may straddle each side of second muscular-walledtube 324.

FIG. 3I illustrates a sensor array for aligning the first sensor 112,the light source 326, and/or the second sensor 114 with themuscular-walled tube, according to an embodiment. Some of the featuresin 3I are the same as or similar to some of the features in FIGS. 1-3Has noted by same reference characters, unless expressly describedotherwise. The sensor array may include a a photosensor or a lightsensor 328 and a light emitter 330. The light sensor 328 and the lightemitter 330 may form an alignment device which may be configured toenable a user to align the first sensor 112 or the second sensor 114with the muscular-walled tube 322 or 324. In an embodiment, the lightsensor 328 may include a photodiode. In an embodiment, the light emitter330 may include a dual band light emitter. In an embodiment, the lightemitter 330 may include two LEDs emitting different wavelengths of lightfrom each other. For example, a first of the LEDs may emit red lightwith a wavelength of approximately 660 nm, and a second of the LEDs mayemit infrared light with a wavelength of approximately 940 nm. Thesensor array may be coupled to the processing device 102 of the wearabledevice 100. The sensor array may straddle the first sensor 112, thelight source 326, and/or the second sensor 114. For example, the twolight sensors 328 may be disposed on opposite sides of the first sensor112, the light source 326, and/or the second sensor 114 from each other.Similarly, the two light emitters 330 may be disposed on opposite sidesof the first sensor 112, the light source 326, and/or the second sensor114 from each other. In an embodiment, the sensor array may straddle themuscular-walled tube 322.

The processing device 102 may include instructions for taking oxygensaturation levels using the sensor array. Light emitted by the lightemitter 330 may be detected by the light sensor 328. The light detectedby the light sensor 328 may correspond to an amount of oxygenatedhemoglobin in the tissue adjacent to the light emitter 330 and the lightsensor 328. A greater amount of oxygenated hemoglobin detected by thelight sensor 328 may indicate the light sensor 328 and the light emitter330 are more closely positioned to the muscular-walled tube 322. In anembodiment, the sensor array may include a set of two light sensors 328and a set of two light emitters 330. A combined signal from the set oftwo light sensors 328 may indicate an alignment with the muscular-walledtube 322. For example, the processing device 102 may store instructionsto compare signals from the two light sensors 328. When the signal fromone of the two light sensors 328 is equal to the signal from another ofthe two light sensors 328, the processing device 102 may provide anindication to a user, such as via the display device 104, that thewearable device 100 is properly aligned on the part of the body 320.

In one example, the alignment device may be embedded in a band of thewearable device around the first sensor 112, the light source 326,and/or the second sensor 114. The alignment device may include a firstdual-band light emitter 330 positioned in the band at a first cornerabout the first sensor 112, the light source 326, and/or the secondsensor 114; a second dual-band light emitter 330 positioned in the bandat a second corner about the first sensor 112, the light source 326,and/or the second sensor 114; a first photosensor 328 positioned in theband at a third corner about the first sensor 112, the light source 326,and/or the second sensor 114; and a second photosensor 328 positioned inthe band at a fourth corner about the first sensor 112, the light source326, and/or the second sensor 114.

In another example, the first dual-band light emitter 330 may bepositioned in the band to be situated along a first side of themuscular-walled tube as the user wears the band; the second dual-bandlight emitter 330 may be positioned in the band to be situated along asecond side of the muscular-walled tube as the user wears the band; thefirst photosensor 328 may be positioned in the band to be situated alongthe first side of the muscular-walled tube as the user wears the band;and the second photosensor 328 may be positioned in the band to besituated along the first side of the muscular-walled tube as the userwears the band. In another example, the first dual-band light emitter330 and the second dual-band light emitter 330 may be positioned in theband to be situated along the first side of the muscular-walled tube asthe user wears the band; and the first photosensor 328 and the secondphotosensor 328 may be positioned in the band to be situated along thesecond side of the muscular-walled tube as the user wears the band.

As shown in FIGS. 3A-H, the second sensor 114 may include miniaturizedelectrode strips. As shown in FIG. 3I, the second sensor 114 may includeelectrode dots. The electrode dots may allow for more precise tuning ofa signal to noise ratio of measurements taken by the second sensor 114.Accordingly, in some embodiments where variability of the signal tonoise ratio may be large, it may be advantageous to manufacture thesecond sensor 114 with electrode dots. Software of a processor coupledto the second sensor 114 may analyze signal quality of a variety ofcombinations of dots and select the pairs of dots with the highestsignal quality. The electrode strips may be simple to manufacture and/ormay require less manufacturing time and/or precision. The electrode dotsmay include a dot surface that may contact the body part. A surface ofthe dot may be approximately equal in length and width dimensions.

Accordingly, in some embodiments where manufacturing considerationsweigh heavy, it may be advantageous to manufacture the second sensor 114with electrode strips. In one example, the electrode strip may have astrip surface that contacts the body part. In another example, the stripsurface may include a length dimension that is greater than a widthdimension of the strip surface.

In one embodiment, a strip of the electrode strips may have a lengthlonger than a width or a thickness of the strip. In one example, acontact surface of the single strip for contacting a body part may beformed by the length and the width. In another example, a thickness ofthe strip may be situated in the band to extend from the band towardsthe wrist as the user wears the wearable device.

FIG. 4A illustrates a perspective view of a miniaturized impedancesensor 400 with an interstitial filler 414 distributed betweenminiaturized electrodes 412, according to an embodiment. Some of thefeatures in FIG. 4A are the same as or similar to some of the featuresin FIGS. 1-3I as noted by same and/or similar reference characters,unless expressly described otherwise. The miniaturized impedance sensor400 may include a growth substrate 402, a first insulating layer 404, aconductive layer 406, a second insulating layer 408, a catalyst layer410, the miniaturized electrode 412, and/or the interstitial filler 414,which elements may be the same as and/or similar to othersimilarly-named elements described and/or illustrated throughout thisdisclosure. In an embodiment, the miniaturized impedance sensor 400 mayinclude one or more of the growth substrate 402, the first insulatinglayer 404, the conductive layer 406, the second insulating layer 408,the catalyst layer 410, the miniaturized electrode 412, and/or theinterstitial filler 414. For example, the miniaturized impedance sensor400 may include a plurality of miniaturized electrodes 412.

The miniaturized impedance sensor 400 may be incorporated into anelectronic device. In various other embodiments, the miniaturizedimpedance sensor 400 may be incorporated into a wearable such as awristband, an armband, a brace such as a knee brace, an ankle brace, anelbow brace, a neck brace, a wrist brace, and/or a back brace, a shirt,a pair of shorts, a pair of pants, a sleeve, a hat, a hardhat, anundergarment, a belt, a pack such as a backpack and/or a fanny pack,headphones, and so forth. In an embodiment, the miniaturized impedancesensor 400 may be incorporated into a wearable device similar to thewearable device 100 described regarding FIG. 1 . For example, the secondsensor 114 of the wearable device 100 may include the miniaturizedimpedance sensor 400. In various embodiments, the miniaturized impedancesensor 400 may be incorporated into a health monitoring device. Thehealth monitoring device may be positioned against a user of the healthmonitoring device to take one or more biometric measurements of theuser. In an embodiment, the health monitoring device may be attached tothe user, such as by an adhesive tape, a therapeutic kinesiology tape,an adhesive bandage, an elastic bandage, a liquid bandage, a gauzebandage, a compression bandage, a cravat bandage, a tube bandage, and soforth. The health monitoring device may include a variety of sensors,such as an optical sensor and a bio impedance sensor. In an embodiment,the health monitoring device may include the miniaturized impedancesensor 400 held against the user by an adhesive tape and electricallycoupled to a computing device. The computing device may include logic, aprocessor, memory, and/or a user interface for communicatingmeasurements by the miniaturized impedance sensor to a person such as ahealthcare professional, and which may allow the person to control theminiaturized impedance sensor 400.

In various embodiments, the miniaturized impedance sensor 400 may beimplemented in other than wearable-device implementations. For example,in an embodiment, the miniaturized impedance sensor 400 may coupled to ahydraulic system. The miniaturized impedance sensor may be attached to asurface that encloses hydraulic fluid to measure a quality and/orintegrity of the hydraulic fluid within the enclosure. In an embodiment,the miniaturized impedance sensor 400 may be incorporated into a devicefor inspecting welds and/or other fabricated materials and/or surfaces.In general, the miniaturized impedance sensor 400 may be used fordetermining a static and/or dynamic quality of a surface and/or volumeof material in a non-invasive way.

The miniaturized impedance sensor 400 may be formed in a layered and/orroughly layered format. As used throughout this disclosure, “layered”may refer to a structure that includes layers of material stacked one ontop of the other in an order. Accordingly, “roughly” layered may referto a structure having layers of material stacked one on top of theother, but the layers may include discontinuities, alternating of theorder, and/or mixing of layers. Though layers of the miniaturizedimpedance sensor 400 may be described in a certain order and/or format,such description is not intended to be limiting. For example, the firstinsulating layer 404 may be disposed between the growth substrate 402and the conductive layer 406 in one embodiment. In another embodimentthe first insulating layer 404 may be integrated with the growthsubstrate 402 to be indistinguishable from the growth substrate 402, andthe conductive layer 406 may be layered on the integrated growthsubstrate 402/first insulating layer 404. In another embodiment, thefirst insulating layer 404 may be disposed between the catalyst layer410 and the miniaturized electrode 412. In an embodiment, theminiaturized impedance sensor 400 may include the growth substrate 402layered underneath the first insulating layer 404. The conductive layer406 may be patterned on the first insulating layer 404. The secondinsulating layer 408 may be deposited over the conductive layer 406. Thecatalyst layer 410 may be patterned on the second insulating layer 408.The miniaturized electrode 412 may be grown on the catalyst layer 410.The interstitial filler 414 may be deposited on the second insulatinglayer 408 surrounding the miniaturized electrode 412.

In one embodiment, the conductive layer 406 may be patterned, where theconductive layer pattern includes regions of conductive materialadjacent to regions of non-conductive material. The regions ofconductive material may be spaced from each other to prevent capacitivecoupling and arcing between the regions of conductive material. In oneexample, the interstitial filler 414 may include a top side and a bottomside. The substrate 402 or the patterned conductive layer 406 may bedisposed at the bottom side of the interstitial filler 414. In anotherexample, a patterned array of miniaturized electrodes 412 may extendthrough a volume from the bottom side to the top side of theinterstitial filler 414.

In various embodiments, elements of the miniaturized impedance sensor400 shown in FIGS. 4A-C may be omitted. For example, the growthsubstrate 402 and/or the first insulating layer 404 may be omitted in anembodiment. In an embodiment where the growth substrate 402 and/or thefirst insulating layer 404 may be omitted, the miniaturized impedancesensor 400 may include the conductive layer 406, the second insulatinglayer 408, the catalyst layer 410, the miniaturized electrode 412,and/or the interstitial filler 414. These elements may be integratedwith another substrate such as a PCB and/or a flexible substrate withelectrical traces. In one embodiment, the miniaturized impedance sensor400 may include the growth substrate 402, the conductive layer 406, thesecond insulating layer 408, the catalyst layer 410, the miniaturizedelectrode 412, and/or the interstitial filler 414, and may omit thefirst insulating layer 404. In another embodiment, the miniaturizedimpedance sensor 400 may include the growth substrate 402, the firstinsulating layer 404, the conductive layer 406, the catalyst layer 410,the miniaturized electrode 412, and/or the interstitial filler 414, andmay omit the second insulating layer 408. In an embodiment, theminiaturized impedance sensor 400 may include the growth substrate 402,the first insulating layer 404, the conductive layer 406, the secondinsulating layer 408, the miniaturized electrode 412, and/or theinterstitial filler 414, and may omit the catalyst layer 410. In anembodiment, the miniaturized impedance sensor 400 may include the growthsubstrate 402, the first insulating layer 404, the conductive layer 406,the second insulating layer 408, and/or the miniaturized electrode 412and may omit the interstitial filler 414.

In various embodiments, the elements of the miniaturized impedancesensor 400 may be provided in a different order and/or may be providedand/or consumed at different stages of a manufacturing process of theminiaturized impedance sensor 400. For example, miniaturized electrode412 may be grown on the growth substrate 402 by laying the medialinsulating layer 408 and the catalyst layer 410 on the growth substrate402. The miniaturized electrodes 412, the medial insulating layer 408,and/or the catalyst layer 410 may be released from the growth substrate402 and the medial insulating layer 408 may be etched away. Theconductive layer 406 may be adhered to the miniaturized electrode 412,such as by a conductive adhesive. Various embodiments and/orarrangements may be selected based on resulting durability of theminiaturized impedance sensor 400, manufacturing constraints, electricalperformance of the miniaturized impedance sensor 400, adhesion of theelements of the miniaturized impedance sensor 400, and so forth.

FIG. 4B illustrates a head-on view of a first side of the miniaturizedimpedance sensor 400 illustrated in FIG. 4A, according to an embodiment.Some of the features in FIG. 4B are the same as or similar to some ofthe features in FIGS. 1-4A as noted by same and/or similar referencecharacters, unless expressly described otherwise. In variousembodiments, the miniaturized impedance sensor 400 may include one ormore dimensions and/or surfaces. For example, the miniaturized impedancesensor 400 may include a back side 416 and a user side 418. The userside 418 may include electrical pads. The electrical pads may be formedby a plurality miniaturized electrodes 412, in one embodiment. The userside 418 of the miniaturized impedance sensor 400 may be positioned inthe wearable device to face a user wearing the wearable device. The userside 418 of the miniaturized impedance sensor 400 may be positioned inthe wearable device to press against a skin surface of the user when theuser wears the wearable device. The back side 416 of the miniaturizedimpedance sensor 400 may be disposed on the miniaturized impedancesensor 400 opposite the user side 418. The back side 416 may bepositioned in the wearable device to form electrical contact between theminiaturized impedance sensor 400 and electronics of the wearabledevice. The back side 416 may include conductors to form such electricalcontact. In an embodiment, the conductors may include the conductivelayer 406. In an embodiment, the conductors may include patterned nickelleads. The miniaturized impedance sensor 400 may include a depth side420. The depth side 420 of the miniaturized impedance sensor 400 may bealigned perpendicular to the user side 418 or the back side 416. In anembodiment, the depth side 420 may be positioned in the wearable deviceto form the electrical contact between the miniaturized impedance sensor400 and the electronics of the wearable device. The depth side 420 mayinclude conductors to form such electrical contact. The conductors mayinclude, in an embodiment, soldering electrically coupled to theconductive layer 406.

The miniaturized impedance sensor 400 may include a height 400 a, awidth 400 b, and/or a length 400 c. The height 400 a may range from 200micrometers (microns) to 1000 microns, from 300 microns to 800 microns,and/or from 400 microns to 600 microns. In an embodiment, the height 400a may be 500 microns. The length 400 c may range from 2 millimeters (mm)to 10 mm, from 3 mm to 8 mm, and/or from 4 mm to 6 mm. In an embodiment,the width 400 b may be 500 microns. The length 400 c may range from 6 mmto 40 mm, from 10 mm to 35 mm, from 15 mm to 30 mm, and/or from 20 mm to25 mm. In an embodiment, the length 400 c may be 2 mm. In an embodiment,the miniaturized impedance sensor 400 may be structured and/orconfigured, such as by the dimensions described above, to occupy avolume ranging from 0.04 cubic millimeters to 20 cubic millimeters. Invarious embodiments the miniaturized impedance sensor 400 may beconfigured to occupy a volume ranging from 0.01 cubic millimeters to0.04 cubic millimeters.

The growth substrate 402 may provide a base support structure fordeposition, growth, and/or etching of various microstructures. Themicrostructures may include the first insulating layer 404, theconductive layer 406, the second insulating layer 408, the catalystlayer 410, the miniaturized electrode 412, or the interstitial filler414. In general, the growth substrate 402 may have low surfaceroughness, such as less than or equal to 1 nanometer (nm). The growthsubstrate 402 may be configured to withstand infiltration of variousmaterials at temperatures ranging up to 1000° C., up to 900° C., and/orup to 850° C. The various materials may include materials from which themicrostructures are formed, such as alumina, nickel, iron, carbon, andso forth. In one embodiment, the growth substrate 402 may include asilicon wafer. In another embodiment, the growth substrate 402 mayinclude a tungsten wafer. In yet another embodiment, the growthsubstrate 402 may include glass such as a borosilicate glass.

In various embodiments, the growth substrate 402 may be removed afterpreparation of the miniaturized impedance sensor 400 and before theminiaturized impedance sensor 400 is incorporated into the wearabledevice. In one embodiment, one or more of the microstructures may bedeposited, grown, and/or etched on the growth substrate 402, and thenremoved from the growth substrate 402 to be integrated into the wearabledevice. For example, the microstructures may be removed from the growthsubstrate 402 and adhered to a flexible substrate for incorporation intothe wearable device. In another embodiment, the growth substrate 402 maybe a reusable substrate that may be used in multiple miniaturizedimpedance sensor preparations. For example, the growth substrate 402 maybe an element of an intermediary state of the miniaturized impedancesensor 400 between preparation of the miniaturized impedance sensor 400and incorporation of the miniaturized impedance sensor 400 into thewearable device. Such an embodiment may be described and/or illustratedin more detail regarding FIG. 8 .

In various embodiments, the growth substrate 402 may be incorporatedwith the miniaturized impedance sensor 400 into the wearable device. Forexample, the growth substrate 402 may act as a support substrate used toincorporate the miniaturized impedance sensor 400 with other electronicsof the wearable device. The growth substrate 402 may include solderedleads which may be electrically coupled to the conductive layer 406 ofthe miniaturized impedance sensor 400. The soldered leads mayelectrically couple the conductive layer 406 to electrical traces in thewearable device. An example of such an embodiment may be describedand/or illustrated in further detail regarding FIG. 9 .

The first insulating layer 404 may provide electrical and/or thermalinsulation between the growth substrate 402 and other microstructures ofthe miniaturized impedance sensor 400. The first insulating layer 404may prevent diffusion of microstructure materials, such as nickel in theconductive layer 406, into the growth substrate 402 during hightemperature growth of the miniaturized electrode 412, where the hightemperatures may range from 700° C. to 1000° C. Additionally, the firstinsulating layer 404 may include a material susceptible to removal by aplasma and/or chemical etch to expose the conductive elements of theminiaturized impedance sensor 400 for integration into circuitry.Alternatively, the first insulating layer 404 may include a materialthat is rendered conductive by one or more processes and/or conditionsduring manufacture of the miniaturized impedance sensor 400. Forexample, alumina may be rendered conductive after exposure totemperatures at which the miniaturized electrode 412 may be grown.

In one embodiment, the first insulating layer 404 may include aluminumoxide (“alumina”). In another embodiment, the first insulating layer 404may include tungsten. The first insulating layer 404 may be deposited onand/or otherwise affixed to the growth substrate 402. For example, thefirst insulating layer 404 may be deposited on the growth substrate 402by sputtering and/or electron beam deposition. Accordingly, a thicknessof the first insulating layer 404 may range from a few nm to a fewmicrons. The first insulating layer 404 may cover an area of the growthsubstrate 402's growth surface corresponding to a set of themicrostructures. The set of microstructures may be disposed on the firstinsulating layer over the area of the growth surface. The set ofmicrostructures may include the conductive layer 406, the catalyst layer410, or the miniaturized electrode 412. The growth substrate 402 mayinclude a set of first insulating layers 404, and each set of firstinsulating layers 404 may include a set of the microstructures.

The conductive layer 406 may provide conductive electrical connectionbetween the miniaturized electrode 412 and the wearable device. Forexample, the conductive layer 406 may be electrically coupled toelectrical traces in the wearable device. Alternatively, the conductivelayer 406 may be electrically coupled to leads on a printed circuitboard (PCB). The conductive layer 406 may be electrically coupled to aPCB by solder bridging the conductive layer 406 to electrical leadscoupled to electrical traces in the PCB. In general, the conductivelayer 406 may be electrically conductive, may easily delaminate from thegrowth substrate after growth of the miniaturized electrode 412, and/ormay have other properties favorable to fabrication and/or manufacturingsuch as solderability. In various embodiments, the conductive layer 406may include nickel, nickel oxide, chromium, stainless steel, aluminumgold, nickel platinum, chromium gold, and so forth. In one embodiment,nickel may have an advantage of being solderable. In another embodiment,the chromium gold may have an advantage being easily released from asilicon wafer.

The conductive layer 406 may be deposited by one or more physical vapordeposition methods such as sputtering deposition and/or evaporationdeposition. The conductive layer 406 may be deposited on the firstinsulating layer 404, then patterned. The patterning may be accomplishedby optical lithography, lift-off, and/or etching for pattern transfer.

The conductive layer 406 may have regions of conductive material, whichmay be referred to as a positive region 422 a. The conductive layer 406may have regions without material, which may be referred to as anegative region 422 b. The positive region 422 a may have a dimensionsuch as an area, and the negative region 422 b may have a dimension suchas an area. The negative region 422 b area may encompass a large enoughvolume and/or surface area to electrically isolate neighboring positiveregions 422 a from each other for amperages and/or potentials up to amaximum level for the device. The maximum current and/or voltage may bethe same as and/or similar to that discussed regarding FIGS. 15A-B. Thenegative region 422 b area may encompass a large enough volume and/orsurface area to electrically isolate each miniaturized electrode 412from each other miniaturized electrode 412. For example, the negativeregion 422 b may have an area ranging from 0.025 mm² to 1 mm². Inanother example, the negative regions 422 b and the positive regions 422a may form two patterns are aligned to form positive regions 422 a thatare conductive regions and negative regions 422 b that arenon-conductive regions. The non-conductive regions electrically mayisolate the conductive regions from each other.

The second insulating layer 408 may contribute to and/or enhance growthof the miniaturized electrode 412. Accordingly, the second insulatinglayer 408 may be complimentary to the catalyst layer 410. The secondinsulating layer 408 may provide a barrier between the catalyst layer410 and the growth substrate 402 and/or the conductive layer 406 toprevent infiltration of the layers into each other. The secondinsulating layer 408 may be rendered conductive by one or moreconditions and/or processes during growth of the miniaturized electrode412. In various embodiments, the second insulating layer 408 may includealumina.

The catalyst layer 410 may provide structural support and/or chemicalreactiveness to stimulate and/or catalyze growth of the miniaturizedelectrode 412. The catalyst layer 410 may be conductive to allow forelectrical conduction between the miniaturized electrode 412 and theconductive layer 406. In various embodiments, the catalyst layer 410 mayinclude iron, cobalt, and/or molybdenum. The catalyst layer 410 may bedeposited on the second insulating layer 408 over the conductive layer406. The catalyst layer 410 may be deposited by a physical vapordeposition technique. In various embodiments, the catalyst layer 410 maybe deposited by sputtering and/or evaporation deposition.

FIG. 4C illustrates a head-on view of a second side of the miniaturizedimpedance sensor 400 illustrated in FIG. 4A, according to an embodiment.Some of the features in FIG. 4C are the same as or similar to some ofthe features in FIGS. 1-4B as noted by same and/or similar referencecharacters, unless expressly described otherwise. As discussedpreviously, various layers of the miniaturized impedance sensor 400 maybe patterned on a preceding layer. A pattern may include the positiveregion 422 a and the negative region 422 b. The positive region 422 amay include material of a patterned layer. The negative region 422 b maylack material of the patterned layer. The first insulating layer 404,the conductive layer 406, the second insulating layer 408, the catalystlayer 410, and/or the miniaturized electrode 412 may be patterned. Asused throughout this disclosure, “positive” may refer to a region of alayer pattern where the layer includes material, and “negative” mayrefer to a region of the layer pattern where the layer lacks material.For example, as illustrated in FIG. 4C, the conductive layer 406 may bepositive where other layers, such as the first insulating layer 404, thesecond insulating layer 408, the catalyst layer 410, and/or theminiaturized electrode 412, are negative. In another example, asillustrated in FIG. 4B, the conductive layer 406 may be positive whereother layers, such as the first insulating layer 404, the secondinsulating layer 408, the catalyst layer 410, and/or the miniaturizedelectrode 412, are positive, and the conductive layer 406 may benegative where other layers, such as the first insulating layer 404, thesecond insulating layer 408, the catalyst layer 410, and/or theminiaturized electrode 412, are negative. In an embodiment, one or moreof the first insulating layer 404, the conductive layer 406, the secondinsulating layer 408, the catalyst layer 410, and the miniaturizedelectrode 412 may be patterned similar to each other. For example,positive regions of various layers, such as the first insulating layer404, the conductive layer 406, the second insulating layer 408, thecatalyst layer 410, or the miniaturized electrode 412, may be aligned.In another embodiment, various layers, such as the first insulatinglayer 404, the conductive layer 406, the second insulating layer 408,the catalyst layer 410, or the miniaturized electrode 412, may bemisaligned.

In an embodiment, the miniaturized electrode 412 may be alignedperpendicular to the growth substrate 402. In an embodiment, theminiaturized electrode 412 may include a bundle of nanotubes runningroughly along the length 400 c. The bundle may be infiltrated with abolstering material, where “bolster” may refer to a property of amaterial that increases resistance against an applied force of thematerial and/or another material with which the material isincorporated. Accordingly, the bolstering material may increase therigidity of the bundle relative to similarly structured bundles notincluding the bolstering material. The bolstering material may reducethe brittleness of the bundle relative to similarly structured bundlesnot including the bolstering material. In various embodiments, thenanotubes may include Carbon Nanotubes (CNTs). The bolstering materialmay include carbon and/or a conductive polymer. In one embodiment, theminiaturized electrode 412 may include CNTs infiltrated with carbon. Inanother embodiment, the nano electrode 412 may include CNTs infiltratedwith a conductive polymer. In another embodiment, the miniaturizedelectrode 412 may include a polymer coated with a conductive film. Theconductive film may include a thin film. The thin film may include metaland/or carbon. In an embodiment, the polymer may be formed into apillar.

In one embodiment, the miniaturized electrode 412 may include an arrayof pillars, such as miniaturized electrode pillars. In one example, thepillar may have a width 412 a and a length 412 b that define a topsurface area of a pillar. In one embodiment, the width 412 and thelength 412 b may be the same. In another embodiment, the width 412 a andthe length 412 b may be different. The array of pillars may include afirst row of miniaturized electrode pillars positioned in a band or awearable device to be aligned approximately perpendicular with adiameter of a muscular-walled tube as the user wears the band; and asecond row of miniaturized electrode pillars positioned in the band tobe aligned approximately perpendicular with the diameter of themuscular-walled tube as the user wears the flexible band. In oneexample, the first row of miniaturized electrode pillars may bepositioned against the dermal layer along the first side of themuscular-walled tube as the user wears the band and the second row ofminiaturized electrode pillars may be positioned against the dermallayer along the second side of the muscular-walled tube as the userwears the band. In another example, the first row of miniaturizedelectrode pillars may be configured in the flexible band to bepositioned against a segment of the dermal layer as the user wears theband. The segment of the dermal layer may be directly adjacent to themuscular-walled tube such that, as the user wears the band, the portionof the dermal layer is situated between the first row of miniaturizedelectrode pillars and the muscular-walled tube.

In another example, the array of miniaturized electrode pillars mayinclude a first row of pillars and a second row pillars. The first rowof pillars and the second row of pillars may be are configured such thatthe electrical signal travels from the first row to the second row. Forexample, the first row of pillars may include a first pillar and asecond pillar and the second row of pillars may include a third pillarand a fourth pillar. In one embodiment, the first pillar and the thirdpillar may be positioned in the band to be situated against the dermallayer along a first side of the muscular-walled tube as the user wearsthe band. In another embodiment, the second pillar and the fourth pillarare positioned in the band to be situated against the dermal layer alonga second side of the muscular-walled tube as the user wears the band.

In another embodiment, a single pillar of the array of miniaturizedelectrode pillars comprising a height greater than a length or a width.In one example, a contact surface of the single pillar may be a dotdefined by the width 412 a and the length 412 b. In another example, aheight 412 c of the pillar may extend from a band towards the wrist asthe user wears the wearable device 100.

According to one embodiment, the interstitial filler 414 may bepositioned between rows and/or columns of microstructures on the growthsubstrate 402. In an embodiment, the interstitial filler 414 may bedeposited on the second insulating layer 408. The interstitial filler414 may fill a region between separate miniaturized electrodes 412. Inanother embodiment, the interstitial filler 414 may be deposited on thegrowth substrate 402 along a first inter-columnar region and may bedeposited on the second insulating layer 408 along a secondinter-columnar region. The interstitial filler 414 may be depositedagainst and/or on the miniaturized electrode 412. For example, theinterstitial filler 414 may be deposited against a side surface 412 d ofthe miniaturized electrode 412. The interstitial filler 414 may adhereto the side surface 412 d. The interstitial filler may be depositedagainst a top surface 412 e of the miniaturized electrode 412. Theinterstitial filler 414 may adhere to the top surface 412 e. In anembodiment, the interstitial filler 414 may include wells 414 a and 414b between neighboring miniaturized electrodes 412. In an embodiment, thewells 414 a and/or 414 b may be rounded, squared, u-shaped, and/orv-shaped. In an embodiment, a top surface 414 c of the interstitialfiller 414 may be disposed against top edges 412 f of the miniaturizedelectrode 412, in an embodiment. The topmost surface may be sloped awayfrom the top edges along the height 412 c of the miniaturized electrode412. In one example, the wells 414 a may dip away from a firstminiaturized electrode or a second miniaturized electrode of theneighboring miniaturized electrodes 412 towards the growth substrate402. In another example, the interstitial filler 414 may include a firsttop surface where the first top surface forms a well 414 a that dipsfrom a first horizontal plane down to a second horizontal plane. Theminiaturized electrodes 412 may include a second top surface. The secondtop surface may be flush with the first horizontal plane and an edge ofthe first top surface of the interstitial filler 414 may be flush withan edge of the second top surface of the miniaturized electrodes 412.

In conventional impedance sensor, breakage of electrodes, may cause theimpedance sensor to malfunction, such as by causing a short in theimpedance circuit. Additionally, depending on a material the electrodesare made of, breakage of the electrodes may cause physiological harm toa user of the impedance sensor. In an extreme example, long-termexposure may lead to disease such as mesothelioma. However, features ofthe miniaturized impedance sensor 400 may prevent such risk, such asinfiltration of the CNTs with the bolstering material and/orreinforcement of the miniaturized electrode 412 with the interstitialfiller 414. The interstitial filler 414 may bolster the miniaturizedelectrode 412 to prevent breakage of the miniaturized electrode 412. Theinterstitial filler 414 may protect the miniaturized electrode 412 fromtorque that may otherwise bend and/or break the miniaturized electrode412. The interstitial filler 414 may be rigid and/or flexible in anembodiment. The interstitial filler 414 may be compressible. In generalthe interstitial filler 414 may include a polymer such as an epoxy. Inone embodiment, the interstitial filler 414 may include polyimide.

FIG. 5A illustrates a perspective view of the miniaturized impedancesensor 400 with the interstitial filler 414 disposed between neighboringminiaturized electrodes 412 in a row, according to an embodiment. Someof the features in FIG. 5A are the same as or similar to some of thefeatures in FIGS. 1-4C as noted by same and/or similar referencecharacters, unless expressly described otherwise. The miniaturizedimpedance sensor 400 may include the growth substrate 402 and/or thefirst insulating layer 404 on which various microstructures may bedeposited, grown, and/or otherwise disposed. The growth substrate 402and/or first insulating layer 404 may be the same as or similar to othersimilarly named elements described and/or illustrated throughout thisdisclosure. The microstructures may include the conductive layer 406,the second insulating layer 408, the catalyst layer 410, theminiaturized electrode 412, and/or the interstitial filler 414, whichelements may be the same as or similar to other similarly named elementsdescribed and/or illustrated throughout this disclosure. Themicrostructures may be layered on the growth substrate 402. In oneembodiment, the microstructures may be arranged in columns 516 and/orrows 518. The interstitial filler 414 may be disposed on the secondinsulating layer 408 between neighboring miniaturized electrodes 412along the same row 518. At least a portion of a growth surface 502 a ofthe growth substrate 402 may remain exposed. In an embodiment, thegrowth surface 502 a may be defined by the length 402 b and/or the width402 c of the growth substrate 402.

FIG. 5B illustrates a head-on view of a first side of the miniaturizedimpedance sensor 400, according to an embodiment. Some of the featuresin FIG. 5B are the same as or similar to some of the features in FIGS.1-5A as noted by same and/or similar reference characters, unlessexpressly described otherwise. Between neighboring miniaturizedelectrodes 412 within the column 516 there is no interstitial filler414. This may allow for flexibility of the miniaturized impedance sensor400 to bend about an axis perpendicular to the column 516. The lack ofinterstitial filler 414 may leave a channel 520 a between twoneighboring rows 518. In an embodiment, the miniaturized electrodes 412may press against skin of a user to take bioimpedance measurements. Thechannel 520 may provide a path for channeling away sweat and/or debristhat may otherwise interfere with the bioimpedance measurements.

FIG. 5C illustrates a head-on view of a second side of the miniaturizedimpedance sensor 400 illustrated in FIG. 5A, according to an embodiment.Some of the features in FIG. 5C are the same as or similar to some ofthe features in FIGS. 1-5B as noted by same and/or similar referencecharacters, unless expressly described otherwise. A section betweenneighboring miniaturized electrodes 412 along the row 518 may includethe interstitial filler 414. The interstitial filler 414 may bondneighboring miniaturized electrodes 412 along the row 518, therebystrengthening the neighboring miniaturized electrodes 412. In anembodiment, the interstitial filler 414 may prevent and/or reduce alikelihood of breakage of the neighboring miniaturized electrodes 412while the channel 520 may allow for flexibility of the miniaturizedimpedance sensor 400. In an embodiment, the miniaturized impedancesensor 400 may be integrated into a flexible athletic band that the usermay wear during athletic and/or other strenuous activities. During suchactivities, the user may move quickly, frequently, and/or may engage ina wide range of movement. The movement of the user may put stress on theflexible athletic band that causes the flexible athletic band to flexquickly, frequently, and/or across a wide range. The channel 520 in theminiaturized impedance sensor 400 may allow the miniaturized impedancesensor 400 to flex with the flexible athletic band as the user moves,while the interstitial filler 414 may maintain rigidity of theminiaturized electrode 412 to prevent breakage as the user moves. Thechannel 520 may additionally allow a path in the miniaturized impedancesensor 400 for channeling away sweat and/or debris as the user moves.

FIG. 6 illustrates a perspective view of the miniaturized impedancesensor 400 with the interstitial filler 414 disposed between rows ofminiaturized electrodes 412, according to an embodiment. Some of thefeatures in FIG. 6 are the same as or similar to some of the features inFIGS. 1-5C as noted by same and/or similar reference characters, unlessexpressly described otherwise. The miniaturized impedance sensor 400 mayinclude the growth substrate 402 and/or first insulating layer 404 onwhich various microstructures may be deposited, grown, and/or otherwisedisposed. The microstructures may include the conductive layer 406, thesecond insulating layer 408, the catalyst layer 410, the miniaturizedelectrode 412, and/or the interstitial filler 414. The microstructuresmay be layered on the growth substrate 402. In one embodiment, themicrostructures may be arranged in columns 616 and/or rows 618. Theinterstitial filler 414 may be disposed on the growth substrate 402between neighboring rows 618. At least a portion of the growth surface502 a of the growth substrate 402 may remain exposed between neighboringminiaturized electrodes 412 along the same row 618. In an embodiment,the interstitial filler 414 may bolster the neighboring rows 618 ofminiaturized electrodes 412.

Because air is a good insulator, various embodiments may include air asthe interstitial filler 414. Because various polymers may have goodstructural strength, various embodiments may include one or morepolymers as the interstitial filler 414. In a general embodiment, theminiaturized impedance sensor 400 may include a first region such aschannel 520 between neighboring miniaturized electrodes 412 a secondregion 620 between neighboring miniaturized electrodes 412. In oneembodiment, The channel 520 may be filled with a polymer such aspolyimide and/or SU-8 to take advantage of the properties of suchmaterials that may make the miniaturized impedance sensor 400 moredurable and/or capable of resisting forces to break the miniaturizedimpedance sensor 400, and the second region 620 may be filled with airto take advantage of the insulating properties of air.

In one example, the miniaturized electrode 412 may have a rectangularcubic shape with a contact surface configured to form electrical contactwith an object external to the miniaturized electrodes 412 or a wearabledevice that miniaturized electrodes 412 are integrated into. Therectangular cubic shape may include a first side and a second sidelonger than the first side. The contact surface may include the firstside or the second side.

FIG. 7A illustrates a side view of the miniaturized impedance sensor 400with circular miniaturized electrodes 412, according to an embodiment.Some of the features in FIG. 7A are the same as or similar to some ofthe features in FIGS. 1-6 as noted by same and/or similar referencecharacters, unless expressly described otherwise. Though shown separatefrom other elements of the miniaturized impedance sensor, the segment700 may be incorporated with other miniaturized impedance sensorelements as described throughout this disclosure. The segment 700 mayinclude the miniaturized electrode 412 and the interstitial filler 414.In an embodiment, the miniaturized electrode 412 may include a circularcolumn of bundled and/or infiltrated nanotubes. The circular column maybe cylindrical. The shape of the miniaturized electrode 412 may causethe wells 414 a to be concave. For example, the interstitial filler 414may be sprayed around the miniaturized electrodes 412 in a solution. Thesolution may be allowed to evaporate, which may reduce an overall volumeof the interstitial filler 414. The interstitial filler 414 may adhereto the miniaturized electrodes 412 as the solution evaporates. This maycause portions of the interstitial filler 414 to slope down and/or awayfrom the miniaturized electrodes 412. In an embodiment where theminiaturized electrodes 412 are cylindrical, the evaporation process maytherefore cause the wells 414 a to be concave.

FIG. 7B illustrates a perspective view of the miniaturized impedancesensor of FIG. 7A, according to an embodiment. Some of the features inFIG. 7B are the same as or similar to some of the features in FIGS. 1-7Aas noted by same and/or similar reference characters, unless expresslydescribed otherwise. The miniaturized electrode 412 may have a top edge702 a and a bottom edge 702 b. The interstitial filler 414 may bedisposed against the miniaturized electrode 412 and/or surround at leasta portion of the miniaturized electrode 412 between the bottom edge 702b and the top edge 702 a. The interstitial filler 414 may be disposedaround the miniaturized electrode 412 against and/or touching the bottomedge 702 b while the top edge 702 a of the miniaturized electrode 412remains exposed from the interstitial filler 414. In an embodiment, thismay increase contact with a user's skin while still providing thestructural support of the interstitial filler 414. The interstitialfiller 414 may include a sloped surface 704 a that slopes up theminiaturized electrode 412 towards the top edge 702 a and away from amain body of the interstitial filler 414. The sloped surface 704 a mayhave a shape complimentary to a shape of the miniaturized electrode 412.In an embodiment, he sloped surface 704 a may be circular.

FIG. 8 illustrates a partially exploded schematic view of theminiaturized impedance sensor 400 electrically coupled to a circuitboard 804, according to an embodiment. Some of the features in FIG. 8are the same as or similar to some of the features in FIGS. 1-7B asnoted by same and/or similar reference characters, unless expresslydescribed otherwise. The miniaturized impedance sensor 400 may includethe conductive layer 406, the second insulating layer 408, the catalystlayer 410, the miniaturized electrode 412, or the interstitial filler414. The circuit board 804 may include a substrate 816, a substrateconductor 818, or an electrical trace 820. The elements of theminiaturized impedance sensor 400 may have been manufactured on a growthsubstrate and base insulating layer, such as the growth substrate 402and the first insulating layer 404. The growth substrate and/or baseinsulating layer may have been removed from the miniaturized impedancesensor 400 to expose the conductive layer 406 for direct contact withthe substrate conductor 818.

The circuit board 804 may provide structural support and/or electronicinterconnectivity of various electronic components integrated into anelectronic device. In various embodiments, the electronic device mayinclude a wearable device, such as the various embodiments of wearabledevices described throughout this disclosure. In various embodiments,the electronic device may include a health monitoring device, such asthe various embodiments of health monitoring devices describedthroughout this disclosure. The circuit board 804 may include a printedcircuit board (PCB), a single-sided PCB, a double-sided PCB, amulti-layer PCB, a rigid PCB, a flex PCB, or a rigid-flex PCB, accordingto an embodiment. The circuit board 804 may be an integrated componentof the wearable device. For example, the wearable device may include aband such as the band 106 illustrated in and described regarding FIGS.1A-C. The band 106 may include the circuit board 804. The circuit board804 may be disposed within the band 106. The circuit board 804 may beintegrated into the band 106. The circuit board 804 may form one or morecomponents of the band 106 such that the circuit board 804 is anintegrated part of the band 106. For example, the band 106 may be formedof the substrate 816 and may have embedded in it the electrical trace820. The circuit board 804 may include a rigid PCB, a flex PCB, and/or arigid-flex PCB.

Although shown and labeled separately in FIG. 8 , in an embodiment,various elements and/or layers of the miniaturized impedance sensor 400may form structural components of the circuit board 804. In anembodiment, the miniaturized impedance sensor 400 may be integrated intoa PCB. For example, the circuit board 804 may include a rigid-flex PCB.In an embodiment, the rigid-flex PCB may include layers of rigidmaterials integrated together with layers of flexible materials. Therigid materials may include the second insulating layer 408 and/or theflexible materials may include the substrate 816. According to anembodiment, the rigid-flex PCB may include a layer of alumina and/or alayer of polyimide, where the second insulating layer 408 includes thealumina and/or the substrate 816 includes the polyimide.

The substrate 816 of the circuit board 804 may be durable, flexible,rigid, compressible, and/or expandable. The substrate 816 may includealumina, aluminum nitride, beryllium oxide, polytetrafluoroethylene(PTFE), polyimide, or polyether ether ketone (PEEK). In an embodiment,the substrate 816 may include a ceramic-filled PTFE composite, ahydrocarbon ceramic laminate, or a glass-reinforced epoxy laminate. Thesubstrate 816 may include layers of material to take advantage ofdifferent properties of different materials. In an embodiment, theelectrical trace 820 may be disposed within the substrate 816, betweentwo layers of the substrate 816, and/or on the substrate 816. In anembodiment, the substrate 816 may extend over and/or around theminiaturized impedance sensor 400 such that an upper section of theminiaturized electrode 412 may be exposed to a user wearing the wearabledevice while a remaining portion of the miniaturized impedance sensormay be disposed within the substrate 816.

The substrate conductor 818 may enable electrical conduction between theminiaturized impedance sensor 400 and the circuit board 804. Thesubstrate conductor 818 may make contact with the conductive layer 406.In an embodiment, the substrate conductor 818 may include electricalsolder, copper, tungsten, and/or nickel. The electrical trace 820 may beelectrically coupled to the substrate conductor. In an embodiment, thesubstrate conductor 818 may include a through-hole through the substrate816. The through-hole may include copper walls connected to a copperelectrical trace 820. The conductive layer 406 may include leads thatextend from the conductive layer 406. The leads may extend into thethrough-hole and form electrical contact with the copper. In anotherembodiment, the substrate conductor 818 may include patterned leads thatmatch a pattern of the conductive layer 406. The conductive layer 406may be set against the patterned leads of the substrate conductor 818.The electrical trace 820 may run through the substrate 816 and formelectrical contact with the substrate conductor.

The electrical trace 820 may carry electrical power and/or signalsbetween the miniaturized impedance sensor 400, the circuit board 804,and/or other electronic components electrically connected to the circuitboard 804. The electrical trace 820 may be electrically coupled to thesubstrate conductor 818 and/or conductors corresponding to otherelectronic components of the wearable device. The electrical trace 820may include a power trace, a ground trace, and/or a signal trace. In anembodiment, the electrical trace may include copper, silver, aluminum,gold, platinum, and so forth.

FIG. 9 illustrates a partially exploded schematic view of theminiaturized impedance sensor 400, according to an embodiment. Some ofthe features in FIG. 9 are the same as or similar to some of thefeatures in FIGS. 1-8 as noted by same and/or similar referencecharacters, unless expressly described otherwise. The miniaturizedimpedance sensor 400 may include the growth substrate 402, the firstinsulating layer 404, the conductive layer 406, the second insulatinglayer 408, the catalyst layer 410, the miniaturized electrode 412, theinterstitial filler 414, soldering 916, and/or an electricalinterconnect 918. In an embodiment, the growth substrate 402 and/orfirst insulating layer 404 may be removed after manufacture of variousmicrostructures of the miniaturized impedance sensor 400, whichmicrostructures may include the conductive layer 406, the secondinsulating layer 408, the catalyst layer 410, the miniaturized electrode412, or the interstitial filler 414. The microstructures may beintegrated into a circuit board, which circuit board may be the same asor similar to other similarly named elements described and/orillustrated throughout this disclosure. The microstructures and/orcircuit board may be integrated into a wearable device, according to anembodiment. In another embodiment, the growth substrate 402 and/or firstinsulating layer 404 may be retained with the microstructures andintegrated with the microstructures into the wearable device. Thewearable device may include the band. The growth substrate 402, thefirst insulating layer 404, and/or the microstructures may be integratedinto the band. In such an embodiment, the growth substrate 402 mayinclude a silicon interposer and/or a fused silica substrate. In oneembodiment, the band may be flexible and the miniaturized impedancesensor 400 may be flexible with locally non-flexible regions. Forexample, the miniaturized impedance sensor 400 may include a firstregion with a non-flexible silicon substrate and a second region with anon-flexible silicon substrate. The first and second regions may beinterconnected by a flexible substance such as polyimide. The first andsecond regions may further be electrically interconnected by conductivetraces in the flexible substance. In another example, a flexible printedcircuit board may be designed to be integrated into a band of awrist-worn device. A shape or a size of the substrate 402 and/or a shapeor a size of the locally non-flexible regions may be designed to flexwith the flexible printed circuit board. In another example, the locallynon-flexible regions may correspond to subsets of the miniaturizedelectrodes 412. In another example, the locally non-flexible regions mayretain their shape as the flexible material changes shape.

In an embodiment, the band may include the electrical trace 820. Theelectrical trace 820 may electrically interconnect various electricalcomponents integrated into the wearable device. The soldering 916 and/orthe electrical interconnect 918 may electrically couple a microstructureof the miniaturized impedance sensor 400, such as the conductive layer406, to the electrical trace 820 of the band. The miniaturized impedancesensor 400 may be electrically coupled to the other electricalcomponents of the wearable device via the electrical trace 820 by thesoldering 916 and/or the electrical interconnect 918. The electricalinterconnect 918 may electrically couple neighboring positive regions ofthe conductive layer 406.

FIG. 10 illustrates a partially exploded schematic view of aminiaturized impedance sensor 400 with an insulating column 1016 betweenneighboring miniaturized electrodes 412, according to an embodiment.Some of the features in FIG. 10 are the same as or similar to some ofthe features in FIGS. 1-9 as noted by same and/or similar referencecharacters, unless expressly described otherwise. The miniaturizedimpedance sensor 400 may include the growth substrate 402, the firstinsulating layer 404, the conductive layer 406, the second insulatinglayer 408, the catalyst layer 410, the miniaturized electrode 412, theinterstitial filler 414, and/or the insulating column 1016. Theinsulating column 1016 may be similar in structure and/or composition tothe miniaturized electrode 412. For example, the insulating column 1016may be grown on the catalyst layer 410 and/or may include bundles ofcarbon-infiltrated CNTs.

The insulating column 1016 may prevent bleeding of current between twominiaturized electrodes 412. In order to measure impedance of amaterial, current is passed between two electrodes through the material.Bleeding of current occurs when current bypasses the material and goesdirectly between the electrodes. This may negatively impact theimpedance measurement. The insulating column 1016 may prevent bleedingof current by providing an alternative path for current that may bleedfrom the miniaturized electrodes 412. The insulating column 1016 may beelectrically coupled to the catalyst layer 410. The catalyst layer 410may be conductive, and/or may be electrically coupled to a ground. Theinsulating column 1016 may provide a path to ground for current that maybleed from the miniaturized electrodes 412. The insulating column 1016may be electrically isolated from the conductive layer 406. The catalystlayer 410 may be patterned such that neighboring positive regions of thecatalyst layer 410 may be electrically isolated from each other.Electrical isolation of the catalyst layer 410 positive regions may beaccomplished by a spacing between neighboring positive regions and/or bycoupling of a positive region coupled to the insulating column 1016 tothe ground.

The insulating column 1016 may be grown and/or situated over a negativeregion of the conductive layer 406, such as the negative regiondescribed and/or illustrated regarding FIGS. 4A-C. The insulating column1016 may increase the rigidity of the reinforced miniaturized impedancesensor 400 relative to a miniaturized impedance sensor embodimentwithout the insulating column 1016. The insulating column 1016 maydecrease a depth of the well 414 a relative to an embodiment without theinsulating column 1016. The depth of the filler well 1014 may bemeasured from a top edge of the miniaturized electrode 412 to a pointlevel with a lowest point of a top surface of the interstitial filler414.

FIG. 11A is a picture of the miniaturized electrode 412 for use in aminiaturized impedance sensor, according to an embodiment. Some of thefeatures in FIG. 11A are the same as or similar to some of the featuresin FIGS. 1-10 as noted by same and/or similar reference characters,unless expressly described otherwise. The miniaturized electrode 412 maybe positioned next to a ruler 1102 with mm tick marks to demonstratesize of the miniaturized electrode. The miniaturized electrode 412 mayhave a width and/or height ranging from 0.1 mm to 2 mm. The miniaturizedelectrode may have a length of 10 mm. The miniaturized electrode 412 mayhave an average density ranging from 1 gram per cubic centimeter (g/cm³)to 2 g/cm³. In an embodiment, the miniaturized electrode 412 may have awidth and/or height of 0.5 mm or 1.0 mm. In an embodiment, a set ofminiaturized electrodes 412 of the miniaturized impedance sensor 400 mayhave an average density of 1.55+/−0.001 g/cm³, 1.50+/−0.05 g/cm³, or1.25+/−0.02 g/cm³.

FIG. 11B is a picture of a nanotube forest 1104 within the miniaturizedelectrode 412, according to an embodiment. Some of the features in FIG.11B are the same as or similar to some of the features in FIGS. 1-11A asnoted by same and/or similar reference characters, unless expresslydescribed otherwise. The picture may show an approximately 12 micron by9 micron area of nanotubes. The miniaturized electrode 412 may have beencut open to reveal the nanotube forest 1104. The nanotube forest 1104may be infiltrated with carbon, as shown by the rough surface of thenanotubes. As described elsewhere herein, the nanotube forest 1104 maybe aligned substantially parallel, with the nanotubes as grown alignedperpendicular to the growth substrate. For example, the nanotube forest1104 may be part of an array of miniaturized electrodes that includes acarbon-infiltrated carbon nanotube forest. The carbon-infiltrated carbonnanotube forest comprises a bundle of aligned carbon nanotubes.

FIG. 11C is a picture of various configurations of rows 1106 a-d ofminiaturized electrodes 412, according to an embodiment. Some of thefeatures in FIG. 11C are the same as or similar to some of the featuresin FIGS. 1-11B as noted by same and/or similar reference characters,unless expressly described otherwise. The rows 1106 a-d of miniaturizedelectrodes 412 may be grown and/or patterned on the growth substrate402. The rows 1106 a-d may include a plurality of the miniaturizedelectrode 412 with the interstitial filler 414 disposed between theminiaturized electrode 412. A first row 1106 a may have aninter-electrode spacing ranging from 50 microns to 150 microns. A secondrow 1106 b may have an inter-electrode spacing ranging from 30 micronsto 70 microns. A third row 1106 c may have an inter-electrode spacingranging from 5 microns to 30 microns. A fourth row 1106 d may have aninter-electrode spacing ranging from less than 1 micron to 10 microns.The miniaturized electrodes 412 may have a height ranging from 50microns to 150 microns. The miniaturized electrodes 412 may have a widthranging from 10 microns to 30 microns. In an embodiment, the first row1106 a may have a center-to-center inter-electrode spacing of 100microns; the second row 1106 b may have a center-to-centerinter-electrode spacing of 60 microns; the third row 1106 c may have acenter-to-center inter-electrode spacing of 15 microns; the fourth row1106 d may have a center-to-center inter-electrode spacing of 5 microns;and the miniaturized electrodes 412 in the rows 1106 a-d may have aheight of 100 microns and a width of 15 microns.

FIG. 11D is a picture of miniaturized electrode pillars 1108, accordingto an embodiment. Some of the features in FIG. 11D are the same as orsimilar to some of the features in FIGS. 1-11C as noted by same and/orsimilar reference characters, unless expressly described otherwise. Theminiaturized electrode pillars 1108 may be grown on the growth substrate402. In general, the miniaturized electrode pillars 1108 may becharacterized by having a height extending from the growth substrate 402that may be greater than a width and/or diameter of the miniaturizedelectrode pillar 1108. The miniaturized electrode pillars 1108 may becircular. The miniaturized electrode pillars 1108 may have a heightranging from 100 microns to 500 microns. The miniaturized electrodepillars 1108 may have a width ranging from 20 microns to 60 microns. Inan embodiment, the miniaturized electrode pillars 1108 may have a widthof approximately 40 microns and a height of approximately 200 microns.

FIG. 11E is a picture of miniaturized electrode strips 1110, accordingto an embodiment. Some of the features in FIG. 11E are the same as orsimilar to some of the features in FIGS. 1-11D as noted by same and/orsimilar reference characters, unless expressly described otherwise. Theminiaturized electrode strips 1110 may be grown on the growth substrate402. In general, the miniaturized electrode strips 1110 may have alength parallel to the growth substrate 402 that may be greater than awidth of the miniaturized electrode strips 1110. In one embodiment, theminiaturized electrode strips 1110 may be formed straight with theminiaturized electrode strips 1110 aligned parallel to each other. Inanother embodiment, the miniaturized electrode strips 1110 may forformed into a pattern such as a zig-zag pattern with the patterns of theminiaturized electrode strips 1110 aligned with each other. Theminiaturized electrode strips 1110 may be formed of the nanotube forest1104.

FIG. 12A illustrates a schematic view of a section of the wearabledevice 100 with an integrated sensor, according to an embodiment. Someof the features in FIG. 12A are the same as or similar to some of thefeatures in FIGS. 1-11E as noted by same and/or similar referencecharacters, unless expressly described otherwise. The wearable device100 may include the miniaturized impedance sensor 400, the band 106,electronic components 1206, and/or an electrical trace 820. Theelectronic components 1206 may include elements the same as or similarto those illustrated in and described regarding FIGS. 1A-C, FIG. 24 ,and/or FIG. 26 . In an embodiment, the miniaturized impedance sensor 400may be integrated into the band 106.

FIG. 12B illustrates a zoomed in view of the sensor illustrated in FIG.12A, according to an embodiment. Some of the features in FIG. 12B arethe same as or similar to some of the features in FIGS. 1-12A as notedby same and/or similar reference characters, unless expressly describedotherwise. The miniaturized impedance sensor 400 may include a substrate1210, the miniaturized electrode 412, the soldering 916, and theelectrical interconnect 918. The substrate 1210 may include a basesubstrate layer such as the growth substrate 402 and/or a flexiblesubstrate, a conductive layer corresponding to the miniaturizedelectrode 412, and/or an interstitial filler between neighboringminiaturized electrodes 412. The electrical interconnect 918 may beembedded in the substrate 1210. The electrical interconnect 918 mayelectrically couple the miniaturized electrode 412 and/or thecorresponding conductive layer to the soldering 916. The soldering 916may be electrically coupled to the electrical trace 820. The electricaltrace 820 may electrically couple the miniaturized impedance sensor 400to a processing device, a power source, or a memory device incorporatedwith the electronic components 1206. The power source may supply powerto the miniaturized impedance sensor 400 so that the miniaturizedimpedance sensor 400 may take a bioimpedance measurement from a userwearing the wearable device. The bioimpedance measurement may bereceived by the processing device. The processing device may utilize thebioimpedance measurement to determine a physiological condition of theuser. The memory device may store the bioimpedance measurement or thephysiological condition. The electronic components 1206 may interactwith the miniaturized impedance sensor 400 in a variety of ways, some ofwhich may be described in more detail regarding other FIGs. in thisdisclosure, such as FIG. 26 .

Neighboring miniaturized electrodes 412 may be arranged in rows whichmay include a first row 1212 a and a second row 1212 b. The neighboringminiaturized electrodes 412 in the same row 1212 a or 1212 b may beinterconnected by the electrical interconnect 918, which mayelectrically couple the row 1212 a or 1212 b to the electrical trace820. In an embodiment, one electrical trace 820 may correspond to onerow 1212 a or 1212 b. In an embodiment, one electrical trace 820 maycorrespond to multiple rows 1212 a and 1212 b. In one embodiment, thefirst row 1212 a may be a positive electrode of a circuit, and thesecond row 1212 b may be a negative electrode of the circuit. The firstrow 1212 a may be electrically coupled to a separate electrical trace820 from the second row 1212 b. In another embodiment, the first andsecond rows 1212 a and 1212 b may both be negative electrodes, andanother row may be the positive electrode. The electrical traces 820connected to each of the first and second rows 1212 a and 1212 b may becombined into a single electrical trace 820 before connecting to theelectronic components. The first and second rows 1212 a and 1212 b mayotherwise be electrically coupled to each other between the miniaturizedimpedance sensor 400 and the electronic components 1206.

The wearable device 100 may be configured in one or more of a variety ofways to enable measurement of one or more of a variety of physiologicalconditions, physiological parameters, and/or physiological constituents.In an embodiment, one or more rows 1212 a and/or 1212 b of miniaturizedelectrodes 412 may be fixed as a positive electrode or a negativeelectrode. In an embodiment, one or more rows of miniaturized electrodes412 may be switchable between acting as a positive electrode and actingas a negative electrode. In an embodiment where rows of miniaturizedelectrodes 412 are switchable, the electrical trace 820 corresponding toa switchable row of miniaturized electrodes 412 may include and/or beelectrically coupled to logic and/or hardware to switch the switchablerow between on, off, positive, and/or negative configurations. In anembodiment, a single row of miniaturized electrodes 412 may be thepositive electrode and the remaining rows of miniaturized electrodes 412of the miniaturized impedance sensor 400 may be the negative electrode.In another embodiment, a single row of miniaturized electrodes 412 maybe the negative electrode and the remaining rows of miniaturizedelectrodes 412 of the miniaturized impedance sensor 400 may be thepositive electrode. One or more of the remaining rows of miniaturizedelectrodes 412 may be switchable between on and/or off configurations.The single row of miniaturized electrodes 412 may be switchable betweenon and/or off configurations.

In various embodiments, a first set of rows of miniaturized electrodes412 may be the positive electrode and a second set of rows ofminiaturized electrodes 412 may be the negative electrode. In one suchembodiment, the first set of rows of miniaturized electrodes 412 may bedisposed on a first end of the miniaturized impedance sensor 400, andthe second set of rows of miniaturized electrodes 412 may be disposed ona second end of the miniaturized impedance sensor 400. In another suchembodiment, the first and second sets of rows of miniaturized electrodes412 may be interspersed such that sequential rows alternate betweenpositive electrode rows and negative electrode rows.

A configuration of the electrical trace 820 may enable switching of therows of miniaturized electrodes 412 between various arrangements ofpositive electrode rows and negative electrode rows. The configurationmay include hardware and/or software logic that may switch theelectrical trace 820 from a positive end of a circuit to a negative endof the circuit. The configuration may include one or more electricalconnections between separate electrical traces 1208 connecting separaterows of miniaturized electrodes 412. A processing device and/or memorydevice electrically coupled by the electrical trace 820 to the rows ofminiaturized electrodes 412 may store machine-readable instructionswhich, when executed by the processing device, may configure the rows ofminiaturized electrodes 412 to a particular electrode configuration(i.e. the positive and negative electrode configurations describedthroughout this disclosure) by the switching logic via the electricaltrace 1208.

FIG. 13A illustrates the wearable device 100 on a wrist 1304 a of auser, according to an embodiment. Some of the features in FIG. 13A arethe same as or similar to some of the features in FIGS. 1-12B as notedby same and/or similar reference characters, unless expressly describedotherwise. The wrist 1304 a may include a first muscular-walled tube1306 a. The first muscular-walled tube 1306 a may be, in an embodiment,a vein or an artery. The wearable device 100 may have an integratedbiometric sensor 1308. The biometric sensor 1308 may include aminiaturized impedance sensor.

The wearable device 100 may be positioned on the wrist 1304 a so thatthe biometric sensor 1308 may be positioned over the muscular-walledtube 1306 a. In an embodiment, the first muscular-walled tube 1306 a maybe positioned in the wrist 1304 a approximate to an underside of thewrist 1304 a. For example, the first muscular-walled tube 1306 a may bepositioned in the wrist 1304 a between a dermal layer of the wrist 1304a and one or more bones in the wrist 1304 a. The biometric sensor 1308may be positioned against the underside of the wrist 1304 a. This mayoptimize an accuracy and/or precision of a measurement taken by thebiometric sensor 1308 from the muscular-walled tube 1306 a. The wearabledevice 100 may use the measurements to determine a physiologicalcondition of the user. Positioning the biometric sensor 1308 against theunderside of the wrist may also reduce a chance of the biometric sensor1308 being struck or otherwise damaged in a way that may affect theaccuracy and/or precision of the measurement taken by the biometricsensor 1308. For example, an outside of the wrist 1304 a may be exposedto other surfaces against which the wearable may be struck, whereas inunderside of the wrist 1304 a may be less likely to strike othersurfaces because it faces towards a body of the user.

FIG. 13B illustrates the wearable device 100 on an arm 1304 b of theuser, according to an embodiment. Some of the features in FIG. 13B arethe same as or similar to some of the features in FIGS. 1-13A as notedby same and/or similar reference characters, unless expressly describedotherwise. The arm 1304 b may include a second muscular-walled tube 1306b. The second muscular-walled tube 1306 b may be, in an embodiment, avein or an artery. The wearable device 100 may be positioned on the arm1304 b so that the biometric sensor 1308 may be positioned over thesecond muscular-walled tube 1306 b.

In various embodiments, the wearable device 100 may be worn by the useron another body part such as a hand of the user, a forearm of the user,an elbow of the user, a chest of the user, a neck of the user, a head ofthe user, a torso of the user, a waist of the user, a thigh of the user,a calf of the user, a knee of the user, an ankle of the user, or a footof the user. Accordingly, the body part may include a muscular-walledtube. The he muscular-walled tube may include an ulnar artery, a radialartery, a brachial artery, a basilic vein, a cephalic vein, an axillaryartery, an axillary vein, a carotid artery, a jugular vein, an iliacartery, a femoral artery, a femoral vein, a tibial artery, a greatsaphenous vein, a dorsalis pedis artery, an arch of foot artery, or atemporal artery.

In various embodiments, the biometric sensor 1308 may be pressed againsta skin surface of the body part. The biometric sensor 1308 and/orwearable device 100 may be positioned on the body part over a region ofthe body part where the muscular-walled tube may be closest to the skinsurface for the body part. The biometric sensor 1308 may be positionedagainst the body part where the muscular-walled tube may be positionedbetween the biometric sensor 1308 and a skeletal structure of the bodypart. This may minimize a distance between the biometric sensor 1308 andthe muscular-walled tube, which in turn may optimize one or morebiometric measurements taken by the biometric sensor 1308 from themuscular-walled tube. In various embodiments, the biometric sensor 1308and/or the wearable device 100 may be positioned on the body part over aregion of the body part where the skeletal structure is positionedbetween the skin surface and the muscular-walled tube. This may maximizethe distance between the biometric sensor 1308 and the muscular-walledtube, which in turn may minimize effects of the muscular-walled tube onmeasurements taken by the biometric sensor 1308. For example, the usermay desire to take a measurement of a relatively static physiologicalcondition, physiological parameter, and/or physiological constituentsuch as a bone density of the user and/or a body fat percentage of theuser. The muscular-walled tube may be dynamic and may interfere withmeasuring the static physiological condition, physiological parameter,and/or physiological constituent. Accordingly, maximizing the distancebetween the biometric sensor 1308 and the muscular-walled tube mayresult in more accurate and/or precise measurements of the staticphysiological condition, physiological parameter, and/or physiologicalconstituent. In various embodiments, the biometric sensor 1308 and/orthe wearable device 100 may be positioned on the body part such that thebiometric sensor 1308 may be approximate the muscular-walled tube andthe skeletal structure such that the muscular-walled tube is not betweenthe skeletal structure and the biometric sensor 1308 and the skeletalstructure is not between the muscular-walled tube and the biometricsensor 1308.

FIG. 14A illustrates impedance paths 1410 for the miniaturized impedancesensor 400 from a side view of the miniaturized impedance sensor 400,according to an embodiment. Some of the features in FIG. 14A are thesame as or similar to some of the features in FIGS. 1-13B as noted bysame and/or similar reference characters, unless expressly describedotherwise. The miniaturized impedance sensor 400 may include a firstsubstrate 1402, a second substrate 1404, the miniaturized electrode 412,and/or the interstitial filler 414, which elements may be the same as orsimilar to other similarly named elements described and/or illustratedthroughout this disclosure. The first substrate may include a circuitboard and/or electrical trace, which elements may be similar to or thesame as other similarly named elements described and/or illustratedthroughout this disclosure. The second substrate 1404 may be layered.The second substrate 1404 may include a first insulating layer such asthe first insulating layer 404, a conductive layer such as theconductive layer 406, a second insulating layer such as the secondinsulating layer 408, and/or a catalyst layer such as the catalyst layer410.

Neighboring miniaturized electrodes 412 may be electricallyinterconnected, such as is illustrated in and described regarding FIGS.12A-B. In an embodiment, within the miniaturized impedance sensor 400,the miniaturized electrodes 412 may be electrically interconnected alonga Y-axis, and/or may be electrically insulated from each other along anX-axis. In another embodiment, the miniaturized electrodes 412 may beelectrically interconnected along the X-axis, and/or may be electricallyinsulated from each other along the Y-axis. The top sides of theminiaturized electrodes 412 may be positioned against a surface. In anembodiment, the surface may include a skin surface of a user wearing awearable device into which the miniaturized impedance sensor 400 may beincorporated. A current may be applied between a first row 1412 ofminiaturized electrodes 412 and a second row 1414 of miniaturizedelectrodes 412. In an embodiment, the first row 1412 of miniaturizedelectrodes 412 may be a positive electrode, and/or the second row 1414of miniaturized electrodes 412 may be a negative electrode. The currentmay follow a path through the surface and/or a subsurface layer.

A measurement of impedance of a surface and/or subsurface layer orelement may indicate a state of the surface and/or subsurface layer orelement. Impedance may be measured by passing current between thepositive electrode and the negative electrode, where the surface and/orsubsurface layer or element may impede at least a portion of thecurrent. The impedance paths 1410 may illustrate the current pathsbetween the positive electrode and the negative electrode. The positiveelectrode and the negative electrode may be electrically coupled to acommon power source which may supply the current. Impedance may beindicated by a voltage or a change in current. In an embodiment, thevoltage may be measured between the positive electrode and the negativeelectrode. The voltage may be used by a processing device to determinean impedance of the surface and/or the subsurface layer. In anotherembodiment, the change in current may be measured between the positiveelectrode and the negative electrode. The change in current may be usedby the processing device to determine the impedance of the surfaceand/or subsurface layer. In an embodiment, the subsurface layer may be asubcutaneous region of the user. Accordingly, the impedance mayrepresent a bioimpedance measurement of the user, in an embodiment.

FIG. 15A illustrates impedance paths of the miniaturized impedancesensor 400 aligned perpendicular to a muscular-walled tube 1510. FIG.15B illustrates impedance paths of the miniaturized impedance sensor 400aligned parallel to the muscular-walled tube 1510. Some of the featuresin FIGS. 15A-B are the same as or similar to some of the features inFIGS. 1-14B as noted by same and/or similar reference characters, unlessexpressly described otherwise. The dermal layers of the user may includean epidermis 1504, a dermis 1506, a hypodermis 1508, and/or an internalelement or subsurface element such as the muscular-walled tube 1510,which elements may be the same as or similar to other similarly namedelements described and/or illustrated throughout this disclosure. Thewearable device 100 may be the same as or similar to other wearabledevices and/or wearable devices described and/or illustrated throughoutthis disclosure. The wearable device 100 may have an embeddedminiaturized impedance sensor 400. The wearable device 100 may includethe band 106, where the band is configured or shaped to press an arrayof miniaturized electrodes of the miniaturized impedance sensor 400 intothe epidermis 1504 or skin of a body part of a user with an optimalpressure. The optimal pressure may maximizes contact of the array ofminiaturized electrodes with the epidermis 1504 or skin and minimizesshunting of capillary sphincters.

The miniaturized impedance sensor 400 may features described and/orillustrated regarding other FIGs. throughout this disclosure. Theminiaturized impedance sensor 400 may include the miniaturized electrode412 and/or the interstitial wells 414 a. In one example, theminiaturized electrode 412 may form and electrical contact with a bodypart, such as the epidermis 1504, and transmit electrical currentthrough the body part to be received at another miniaturized electrode.

Conventional bioimpedance sensors may include pads. The pads may have awide area, such as an area measured in square millimeters and/or squarecentimeters. The pads may additionally be formed of a relatively roughand/or porous material when compared with human skin, especially skinalong areas of body parts with veins and/or arteries close to thesurface of the skin. The features of the pads relative to the skin mayresult in poor initial conductive contact between the pads and the skin.In such configurations, the present inventors have discovered that theremay be an “acclimation period” at the end of which time the padmaximizes conductive contact with the skin of a user. The acclimationperiod may last approximately 30 minutes. During the acclimation period,measurements taken using the bioimpedance sensor may be unreliable.Other factors may cause the measurements to be unreliable. For example,sweat and/or debris may accumulate between the pads and the skin whichmay result in poor conductive contact between the pads and the skin.Such accumulation may lead to further unreliability of measurements.Various embodiments throughout this disclosure may address theunreliability of bioimpedance sensors having relatively large, rough,and/or porous pads, in addition to improving upon other previoussolutions in various ways.

The wearable device 100 may be pressed against the epidermis 1504. Inone embodiment, the miniaturized electrode 412 may protrude from asurface 1518 of the wearable device 100. The interstitial well 414 a maybe flush with the wearable device surface 1518 to form a continuoussurface with the wearable device surface 1518. The top portion of theminiaturized electrode 412 may press into the epidermis 1504. The topportion of the miniaturized electrode 412 may deform the regions of theepidermis 1504 immediately surrounding the top portion of theminiaturized electrode 412 with little or no deformation of otherregions of the epidermis 1504 such as those regions against the wearabledevice surface 1518. The top portion of the miniaturized electrode 412may form smooth and/or complete contact with the epidermis 1504. Theepidermis 1504 may flex and/or form into the interstitial well 414 a.The interstitial well 414 a may provide a channel for collecting and/orchanneling away sweat and debris from the miniaturized electrode 412and/or epidermis 1504. This may further improve contact between the topportion of the miniaturized electrode 412 and the epidermis 1504 byproviding an outlet for debris and/or sweat that may otherwiseaccumulate between the epidermis 1504 and the miniaturized electrode412. The miniaturized electrode 412 may be formed of a smooth and/ornon-porous material that may additionally improve contact between theminiaturized electrode 412 and the epidermis 1504. For example, in oneembodiment the miniaturized electrode 412 may be formed of CNTs coatedwith polyimide.

In one embodiment, a top surface 1522 of the miniaturized electrode 412may be flush with the wearable device surface 1518 to form a continuoussurface with the wearable device surface 1518. The miniaturizedelectrode 412 may be formed of the smooth and/or non-porous materialsuch that the miniaturized electrode 412 may form continuous contactwith the epidermis 1504. The top surface 1522 may contact the epidermis1504 without deforming the epidermis 1504. This may improve accuracy ofmeasurements taken by the miniaturized impedance sensor 400 by ensuringconstant, complete contact with the epidermis 1504 without altering theepidermis 1504 in a way that may affect a measurement take from theepidermis 1504.

The top surface 1522 may have a surface area. The size of the surfacearea relative to a thickness of the epidermis 1504 may minimize animpact the wearable device 100 and/or miniaturized impedance sensor 400may have on various physiological conditions, physiological parameters,and/or physiological constituents of the user. For example, in order toensure accurate measurement, a bioimpedance sensor may be pressedagainst the epidermis 1504. However, pressing on the epidermis 1504 tohold the sensor against the epidermis 1504 may deform the dermal layersand/or various subdermal features of the user. The deformation may alterthe physiological condition, physiological parameter, and/orphysiological constituent the user desires to measure. For example,pressing on the epidermis 1504 may cause blood to be forced out ofcapillaries. Reducing the size of the electrodes may reduce the amountof force required to maintain sufficient contact between the electrodesand the epidermis 1504. This may in turn reduce a degree to which theepidermis 1504, the dermis 1506, and/or the hypodermis 1508 may bedeformed. In an embodiment, an optimal surface area for minimallydeforming the skin may range from 100 microns² to 500 microns² for eachelectrode. At this scale, the acclimation period for maximizingconductive contact between the miniaturized electrode 412 and theepidermis 1504 may be significantly reduced. In an embodiment, theacclimation period may be reduced from a range of 5 minutes to 15minutes to a range less than or equal to 1 minute. In one embodiment,the acclimation period may be eliminated.

Miniaturization of the electrodes to the microscale as described hereinmay allow for optimal contact of the miniaturized electrodes 412 withthe epidermis 1504. Optimal pressure of the miniaturized electrodes 412into the epidermis 1504 may result in conformation of the epidermisaround the miniaturized electrodes 412, up to and/or including contactof the epidermis 1504 with the interstitial well 414 a. Conformation ofthe epidermis 1504 may optimally enhance signal response from themuscular-walled tube 1510 and/or fluid within the muscular-walled tube1510 by the miniaturized electrodes 412. The pressure of theminiaturized electrodes 412 into the epidermis 1504 may be low enough toprevent and/or minimize shunting of capillary sphincters either open orclose, which may generate physiological noise which may interfere withthe signal from the muscular-walled tube 1510.

Incorporation of the miniaturized electrodes 412 into the miniaturizedimpedance sensor may allow for incorporation of a plurality ofminiaturized electrodes 412 for measuring to a variety of subcutaneousdepths. The miniaturized electrodes 412 may include a material that maybe formed and/or manipulated on the scale of the surface area range.Such material may include CNTs. The CNTs may be formed into pillars withsmooth surfaces on the scale of the surface area range. Additionally,the pillars may be electrically isolated from each other while stillallowing for a plurality of electrodes for taking measurement at aplurality of depths.

A path of a current passed between the first miniaturized electrode andthe second miniaturized electrode may depend on the size of the currentand/or a separation distance between the first miniaturized electrodeand the second miniaturized electrode, according to an embodiment. Forexample, the current may follow a first impedance path 1520 a between apositive electrode 1514 a and a first negative electrode 1514 b. Thefirst impedance path 1520 a may pass through the epidermis 1504 and/orthe dermis 1506. A measurement taken along the first impedance path 1520a may measure an impedance of the epidermis 1504 and/or the dermis 1506.A physiological condition, physiological parameter, and/or physiologicalconstituent of the epidermis 1504 and/or the dermis 1506 may bedetermined by the measurement taken along the first impedance path 1520a. In an embodiment, the physiological condition may include a hydrationcondition of the user of the wearable device 100.

The current may follow a second impedance path 1520 b between thepositive electrode 1514 a and a second negative electrode 1514 c. Thesecond impedance path 1520 b may pass through the epidermis 1504, thedermis 1506, and/or the hypodermis 1508. A measurement taken along thesecond impedance path 1520 b may measure an impedance of the epidermis1504, the dermis 1506, and/or the hypodermis 1508. A physiologicalcondition, physiological parameter, and/or physiological constituent ofthe epidermis 1504, the dermis 1506, and/or the hypodermis 1508 may bedetermined by the measurement take along the second impedance path 1520b. In an embodiment, the physiological parameter may include a body fatpercentage of the user of the wearable device 100.

The current may follow a third impedance path 1520 c between thepositive electrode 1514 a and a third negative electrode 1514 d. Thesecond impedance path 1520 b may pass through the epidermis 1504, thedermis 1506, the hypodermis 1508, and/or the muscular-walled tube 1510.A measurement taken along the third impedance path 1520 c may measure animpedance of the epidermis 1504, the dermis 1506, the hypodermis 1508,and/or the muscular-walled tube 1510. A physiological condition,physiological parameter, and/or physiological constituent of theepidermis 1504, the dermis 1506, the hypodermis 1508, and/or themuscular-walled tube 1510 may be determined by the measurement takenalong the third impedance path 1520 c. In an embodiment, thephysiological constituent may include a blood glucose level of a user ofthe wearable device 100.

In an embodiment, a negative electrode closest to the positive electrode1515 a may be separated from the positive electrode 1514 a by a distancesuch that the current passes through the epidermis 1504 without passingthrough the dermis 1506. The negative electrode closest to the positiveelectrode 1514 a may be separated from the positive electrode 1514 a bya distance such that the current passes through the epidermis 1504and/or the dermis 1506 without passing through the hypodermis 1508,according to an embodiment. The negative electrode closest to thepositive electrode 1514 a may be separated from the positive electrode1514 a by a distance such that the current passes through the epidermis1504, the dermis 1506, and/or the hypodermis 1508 without passingthrough the muscular-walled tube 1510. In an embodiment, the negativeelectrode closest to the positive electrode 1514 a may be separated fromthe positive electrode 1514 a by a distance such that the current passesthrough the epidermis 1504, the dermis 1506, the hypodermis 1508, and/orthe muscular-walled tube 1510. In an embodiment, the negative electrodeclosest to the positive electrode 1514 a may be separated from thepositive electrode 1514 a by a distance such that the current passesthrough the epidermis 1504, the dermis 1506, the hypodermis 1508, themuscular-walled tube 1510, and/or deeper tissue.

In one embodiment, the miniaturized impedance sensor 400 may bepositioned against the user such that the current may flow perpendicularto the muscular-walled tube 1510 as the current passes from the positiveelectrode 1514 a to the first negative electrode 1514 b, the secondnegative electrode 1514 c, and/or the third negative electrode 1514 d.In another embodiment, the miniaturized impedance sensor 400 may bepositioned against the user such that the current may pass through themuscular-walled tube 1510 along a length of the muscular-walled tube1510 as the current passes from the positive electrode 1514 a to thefirst negative electrode 1514 b, the second negative electrode 1514 c,and/or the third negative electrode 1514 d.

In various embodiments, the first impedance path 1520 a, the secondimpedance path 1520 b, and/or the third impedance path 1520 c may besymmetrical and/or smooth In another embodiment, the first impedancepath 1520 a, the second impedance path 1520 b, and/or the thirdimpedance path 1520 c may vary over time across a region of the materialas the conductive properties of the material change to change the pathof least resistance for the current. The illustrated impedance paths maybe provided to aid in describing the properties, features, and/orfunctions of various elements of embodiments throughout this disclosure.Accordingly, the illustrated impedance paths are not intended to belimiting of the path followed by a flow of current through a material.

In an embodiment, one or more miniaturized electrodes 412 may beelectrically coupled to a processing device such that the processingdevice may assign the miniaturized electrode 412 to be the positiveelectrode and/or the negative electrode. The miniaturized impedancesensor 400 may include a number of rows of miniaturized electrodes 412,with a number of miniaturized electrodes 412 in each row. In someembodiments, a row of miniaturized electrodes 412 may include a singlestrip electrode. In some embodiments, a row of miniaturized electrodes412 may include two or more miniaturized electrodes 412. For example, arow of miniaturized electrodes 412 may include 1 to 40 miniaturizedelectrodes 412, 5 to 35 miniaturized electrodes 412, 10 to 30miniaturized electrodes 412, and/or 15 to 25 miniaturized electrodes412. In one embodiment, a row of miniaturized electrodes 412 may include5 miniaturized electrodes 412. Having a plurality of rows may allow formeasurement of different depths within a material, substance, and/orbody using the same sensor. Having a plurality of miniaturizedelectrodes 412 in each row may increase a surface area of the covered bythe row, which may in turn reduce negative effects associated with, forexample, debris and/or sweat. Having a plurality of miniaturizedelectrodes 412 in each row may also increase the structural strength ofthe miniaturized impedance sensor 400, such as the resistance of theminiaturized impedance sensor 400 to deforming and/or or breaking undervarious stresses.

The number of rows, the number of miniaturized electrodes 412 in eachrow, a spacing between rows, and/or a spacing between each miniaturizedelectrode 412 may correspond to a diameter and/or cross-sectionaldimension of a body part on which a user wears the wearable device 100incorporating the miniaturized impedance sensor 400. For example, thebody part may be a wrist of the user. The spacing between the rows ofminiaturized electrodes 412 spaced furthest from each other may beenough that current passed between the rows passes from an epidermallayer on an underside of the wrist and through an epidermal layer on atopside of the wrist opposite the underside. The underside of the wristmay face towards the user's body as the arm hangs in a resting position,and the topside may face away from the user's body as the arm hangs in aresting position. The spacing between each row of the miniaturizedimpedance sensor 400 may be such that the user may select depths intothe wrist from the miniaturized impedance sensor 400 in incrementsranging from 5 cm to 50 microns. Having a plurality of rows ofminiaturized electrodes 412 may allow the miniaturized impedance sensor400 to be adapted to different body parts and different users.

Different users may have differently-sized body parts. A thickness of adermal layer may be different for one user for one body part than for adifferent user for the same body part. A depth of a muscular-walled tubemay be different for one user for one body part than for a differentuser for the same body part. A thickness of a dermal layer of one bodypart may be different for one user than a thickness of a dermal layer ofa different part for the same user. A depth of a muscular-walled tubemay be different for one body part of a user than a depth of amuscular-walled tube for a different body part of the same user. Theplurality of miniaturized electrodes 412 incorporated into theminiaturized impedance sensor 400 may allow for one design of theminiaturized impedance sensor 400, include dimensions, numbers ofelectrodes, and electrode spacing, to accommodate a wide variety ofusers and/or user body parts.

Having a plurality of rows of miniaturized electrodes 412, which eachrow selectable as a positive electrode or negative electrode, may allowfor dynamic selecting of a depth to measure and/or a physiologicalcondition, physiological parameter, and/or physiological constituent tomeasure. For example, for a fixed current, a spacing between thepositive and negative electrode may be varied until a selected depth isreached. In one embodiment, for a fixed spacing, the current may bevaried until a selected signal strength is reached. In one embodiment,the current and the spacing may be varied until a selected signalstrength is reached. In an embodiment, a particular waveform associatedwith a particular physiological condition, physiological parameter,and/or physiological constituent may be established. The spacing and/orthe current may be varied until the miniaturized impedance sensor 400outputs the established waveform.

The miniaturized impedance sensor 400 may be configured to takemeasurements at various depths into the body part at various increments.A particular physiological condition, physiological parameter, and/orphysiological constituent may correspond to a particular depth and/orrange of depths into the body part. A memory device electrically coupledto the processing device may store data correlating a list ofphysiological conditions, physiological parameters, and/or physiologicalconstituents with a list of depths into the body part. The processingdevice may obtain, from the memory device, the depth and/or range ofdepths associated with a selected physiological condition, physiologicalparameter, and/or physiological constituent. The processing device maychoose a row of miniaturized electrodes 412 to act as a positiveelectrode and one or more rows of miniaturized electrodes 412 to act asnegative electrodes corresponding to the depth associated with theselected physiological condition, physiological parameter, and/orphysiological constituent. The processing device may activate theselected positive and negative electrode rows such that electricalcurrent passes from the positive electrode row, through the body part tothe associated depth, and to the negative electrode row or rows. Theprocessing device may measure the impedance between the positive andnegative electrode rows. The processing device may compare the resultingimpedance to data stored in the memory device which may correlate a listof impedances with the list physiological conditions, physiologicalparameters, and/or physiological constituents and the list of depths.

In one embodiment, a body part includes a first subdermal feature at afirst depth within the body part and a second subdermal feature at asecond depth within the body part deeper than the first depth. In oneexample, the first subdermal feature and/or the subdermal feature is theepidermis 1504, the dermis 1506, the hypodermis 1508, themuscular-walled tube 1510, and/or deeper tissue. In another example, thefirst subdermal feature and the second subdermal feature are positionedin a same region of the body part.

In another embodiment, the miniaturized impedance sensor 400 may includea first miniaturized electrode 1514 a-d to transmit an electronic signalthrough the body part as the user wears the band. In one example, theelectronic signal is transmitted at a first power level or a secondpower level. In another embodiment, the miniaturized impedance sensor400 includes a second miniaturized electrode 1514 a-d spaced from thefirst miniaturized electrode at a first distance. The first distance maybe a distance so that the second miniaturized electrode 1514 a-dreceives the electronic signal from the first miniaturized electrode1514 a-d through the first subdermal feature when the user wears theband. In one example, the electronic signal may bypass the secondsubdermal feature when it is received by the second miniaturizedelectrode 1514 a-d. In another example, the first distance ma be lessthan first threshold distance to prevent the electric signal frompenetrating into the body part to a depth of the second subdermalfeature.

In another embodiment, the miniaturized impedance sensor 400 may includea third miniaturized electrode 1514 a-d spaced from the firstminiaturized electrode 1514 a-d at a second distance. In one example,the second distance is greater than the first distance. In anotherexample, the third miniaturized electrode 1514 a-d receives theelectronic signal from the first miniaturized electrode through thesecond subdermal feature when the user wears the band. In one example,when the first miniaturized electrode 1514 a-d transmits the electricsignal at the first power level and at the first distance from thesecond miniaturized electrode 1514 a-d, the first miniaturized electrodegenerates a circular electric field in the body part as the user wearsthe band. In another example, when the first miniaturized electrode 1514a-d transmits the electric signal at the second power level and at thesecond distance from the second miniaturized electrode 1514 a-d, thefirst miniaturized electrode 1514 a-d generates an elliptical electricfield in the body part as the user wears the band.

In another example, the first miniaturized electrode 1514 a-d and thesecond miniaturized electrode 1514 a-d or the first miniaturizedelectrode 1514 a-d and the third miniaturized electrode 1514 a-d arepositioned in a band of a wearable device such that: as the user wearsthe band a first electric field between the first miniaturized electrode1514 a-d and the second miniaturized electrode 1514 a-d or between thefirst miniaturized electrode 1514 a-d and the third miniaturizedelectrode 1514 a-d is aligned parallel to a muscular-walled tube 1510 ofa body part, such as the hypodermis 1508; or a second electric fieldbetween the first miniaturized electrode 1514 a-d and the secondminiaturized electrode 1514 a-d or between the first miniaturizedelectrode 1514 a-d and the third miniaturized electrode 1514 a-d isaligned perpendicular to the muscular-walled tube 1510.

In one example, a processing device coupled to the miniaturizedelectrode 1514 a-d may automatically select a pair of miniaturizedelectrodes 1514 a-d from the array of miniaturized electrodes 1514 a-dbased on an impedance signal generated by the pair of miniaturizedelectrodes 1514 a-d. In one example, the first miniaturized electrode1514 a-d is configured in the miniaturized impedance sensor to transmitthe electronic signal at a discreet frequency or at a spectrum ofdifferent frequencies. In another example, the processing device maymeasure an impedance of the first subdermal feature or the secondsubdermal feature for a spectrum of frequencies by transmitting theelectronic signal from the first miniaturized electrode 1514 a-d at thefirst power level or the second power level and across the spectrum offrequencies.

In another example, the processing device may iteratively selecttransmitting the electronic signal between the first miniaturizedelectrode 1514 a-d and the second miniaturized electrode 1514 a-d andbetween the first miniaturized electrode 1514 a-d and the thirdminiaturized electrode 1514 a-d until the miniaturized impedance sensordetects the electronic signal indicative of a threshold impedancemeasurement. In another example, the processing device may iterativelyselect a frequency from a spectrum of different frequencies until theminiaturized impedance sensor detects the electronic signal indicativeof the threshold impedance measurement. The threshold impedancemeasurement may correspond to a measurement taken at the first subdermalfeature or the second subdermal feature.

In another example, the processing device may apply power via a powersource to the first miniaturized electrode such that the firstminiaturized electrode 1514 a-d transmits a first signal when the userselects, via the user interface, a first measurement corresponding tothe first subdermal feature. In another example, the processing devicemay apply power via the power source to the second miniaturizedelectrode 1514 a-d such that the second miniaturized electrode 1514 a-dtransmits a second signal when the user selects, via a user interface, asecond measurement corresponding to the second subdermal feature. Inanother example, a processing device may select a depth from themultiple depths at which the impedance is measured. The processingdevice may select the depth that corresponds to a subdermal featurewithin the body part based on a spacing between the first miniaturizedelectrode 1514 a-d and the second miniaturized electrode 1514 a-d.

In another example, the processing device may measure impedance at anumber of depths within the body part as the user wears the band, wherethe number of depths correspond to a number of electrically separateminiaturized electrodes of an array of miniaturized electrodes. Inanother example, the processing device may select a pair of miniaturizedelectrodes based on a difference between a first signal to noise ratiocorresponding to a first subdermal feature of the body part and a secondsignal to noise ratio corresponding to a second subdermal feature of thebody part. In another example, the processing device may compare theimpedance of the electronic signal to defined impedance values measuredusing different miniaturized electrodes 1514 a-d. In another example,the defined impedance values may be associated with one or more featuresof the body part. In another example, the processing device maycorrelate a change in the impedance with a change in the body part 1508.The body part 1508 may include the muscular-walled tube 1510 within thebody part. The muscular-walled tube 1510 may have blood flowing throughthe muscular-walled tube 1510. The change may include a change in anamount of glucose in the blood flowing through the muscular-walled tube1510.

FIGS. 16A-B illustrate graphs showing electric field lines 1602 betweena first miniaturized electrode 1604 and a second miniaturized electrode1606 of a miniaturized impedance sensor such as the miniaturizedimpedance sensor 400. The first miniaturized electrode 1604 and/or thesecond miniaturized electrode 1606 may be the same as or similar to theminiaturized electrode 412 described and illustrated throughout thisdisclosure. A vertical axis 1608 may show a depth the electric fieldlines 1602 penetrate into a substance in meters, and a horizontal axis1610 may show a separation distance between the first miniaturizedelectrode 1604 and the second miniaturized electrode 1606 in meters. Adensity of the electric field lines 1602 may indicate a strength of anelectric field at a point in the substance. In an embodiment, thesubstance may include a dermal and/or subdermal region of a user wearinga wearable device such as is described and/or illustrated throughoutthis disclosure. FIG. 16A illustrates the first electrode 1604 and thesecond electrode 1606 separated by approximately 0.04 m. FIG. 16Billustrates the first electrode 1604 and the second electrode 1606separated by approximately 0.01 m.

A greater separation between the first electrode 1604 and the secondelectrode 1606 may correlate with a deeper penetration of the electricfield into the substance. For example, a separation of 0.01 m maycorrespond to a penetration of 0.03 m, whereas a separation 0.04 m maycorrespond to a penetration of at least 0.04 m. As the separationdistance between the first electrode 1604 and the second electrode 1606changes, a shape of the electric field may also change. For example, asthe separation distance increases from 0.01 m to 0.04 m, the shape ofthe electric field may change from circular to oblong. A particularshape of the shape of the electric field may be suited for a particulara physiological condition, physiological parameter, and/or physiologicalconstituent. For example, an oblong shape may be suited to measure aphysiological condition, physiological parameter, and/or physiologicalconstituent that corresponds to an average measurement of a volume. Acircular shape may be suited to measure a physiological condition,physiological parameter, and/or physiological constituent thatcorresponds to a cross-sectional area. The shape of the electric fieldmay be varied by the number and/or relative positions of the electrodes.For example, a single positive electrode may be positioned between twonegative electrodes. The spacing of the electrodes and the strength ofthe current may create two side-by-side circular electric fields. Oneelectric field may pass through a cross-section of a vein; the otherelectric field may pass through a cross-section of an artery. Theside-by-side arrangement may be used to compare blood constituents ofblood flowing to a body part with blood flowing from the body part.

The miniaturized impedance sensor may have a number of positive-negativepairs of miniaturized electrodes, which may allow for selection of thephysiological condition, physiological parameter, and/or physiologicalconstituent to be measured by the miniaturized impedance sensor. Thespacing between the positive-negative pair may determine the depth fromwhich the miniaturized impedance sensor may take a measurement.Incorporating a number of positive-negative pairs of miniaturizedelectrodes, each pair having a different spacing from each other pair,may accordingly allow for measurement to different depths by a singleminiaturized impedance sensor. For example, a first pair of miniaturizedelectrodes of the miniaturized impedance sensor may be separated byapproximately 0.01 m, and a second pair of miniaturized electrodes ofthe miniaturized impedance sensor may be separated by approximately 0.04m. The first pair of miniaturized electrodes may take a measurementcorresponding to a physiological condition at 0.005 m beneath a surfaceof skin of a user, such as a hydration condition of the user. The firstpair of nano electrodes may measure an impedance of the skin. The secondpair of nano electrodes may take a measurement corresponding to aphysiological condition at 0.01 m beneath the surface of the skin, wherea vein or artery may be located. The second pair of nano electrodes maymeasure an impedance of blood in the vein or artery, which may beprocessed by a processing device to determine respective quantities ofvarious constituents of the blood.

FIGS. 17A-B illustrate a first set of miniaturized electrodes 1702 and asecond set of miniaturized electrodes 1704 against a user 1706,according to an embodiment. Some of the features in FIGS. 17A-B are thesame as or similar to some of the features in FIGS. 1-16B as noted bysame and/or similar reference characters, unless expressly describedotherwise. FIG. 17A illustrates impedance paths 1718 aligned parallel toan artery 1714. FIG. 17B illustrates impedance paths 1718 alignedperpendicular to the artery 1714. The first set of electrodes 1702 maybe electrically coupled to a current source 1708. In an embodiment, thecurrent source 1708 may include a voltage to current converter, which bethe same as or similar to the voltage to current converter 1806described and/or illustrated regarding FIG. 18 . The second set ofelectrodes 1704 may be electrically coupled to a voltmeter 1710. In anembodiment, the voltmeter may include an operational amplifier, whichmay be the same as or similar to the operational amplifier 1816described and/or illustrated regarding FIG. 18 . The first set ofminiaturized electrodes 1702 may cause a current to be passed throughthe skin 1706, a subcutaneous tissue 1712, and/or the artery 1714. Thesecond set of miniaturized electrodes 1704 may be placed between the twoelectrodes of the first set of miniaturized electrodes 1702 to measure avoltage between the two electrodes of the first set of miniaturizedelectrodes 1702. The resulting voltage may be subsequently used todetermine an impedance of the skin 1706, the subcutaneous tissue 1712,and/or the artery 1714. In an embodiment, an impedance of the artery1714 may include an impedance of substances found within the artery1714, such as blood and/or various blood constituents.

Arrows 1716 may indicate an expansion of the artery 1714 as blood ispumped through the artery 1714 by a heart. The artery may expandaccording to a heartbeat of the heart. Expansion of the artery 1714 maychange a volumetric composition of a volume for which the impedance ismeasured. The change in the volumetric composition may change theimpedance in cadence with the heartbeat. Accordingly, changes inimpedance may be caused by the heartbeat, and may be correlated directlywith a condition, parameter, and/or constituent of the heart and/orcirculatory system.

17C illustrates an electronic schematic of the miniaturized electrodesdescribed regarding FIGS. 17A-B, according to an embodiment. Some of thefeatures in FIG. 17C are the same as or similar to some of the featuresin FIGS. 1-17B as noted by same and/or similar reference characters,unless expressly described otherwise. The first set of miniaturizedelectrodes 1702 and second set of miniaturized electrodes 1704 may bestructured as bars. The bars may be aligned perpendicular to a length ofthe artery 1714. The first set of miniaturized electrodes 1702 mayinclude the first miniaturized electrode 1702 a and the secondminiaturized electrode 1702 b. The second set of miniaturized electrodes1704 may include the third miniaturized electrode 1704 a and the fourthminiaturized electrode 1704 b.

The second set of miniaturized electrodes 1704 may be set between thefirst miniaturized electrode 1702 a and the second miniaturizedelectrode 1702 b. The third miniaturized electrode 1704 a may bepositioned closer to the first miniaturized electrode 1702 a than to theother miniaturized electrode of the second set, miniaturized electrode1704 b. Similarly, the fourth miniaturized electrode 1704 b may bepositioned closer to the second miniaturized electrode 1702 b than tothe third miniaturized electrode 1704 a. For example, a distance betweenthe miniaturized electrodes of the first set 1702 may range from 0.5 cmto 3 cm, from 0.75 cm to 2 cm, and/or from 1 cm to 1.5 cm. A distancebetween the miniaturized electrodes of opposing sets, such as betweenthe first miniaturized electrode 1702 a and the third miniaturizedelectrode 1704 a, and/or between the second miniaturized electrode 1702b and the fourth miniaturized electrode 1704 b, may be a fraction of thedistance between the miniaturized electrodes of the first set 1702. Forexample, a distance between the first miniaturized electrode 1702 a andthe third miniaturized electrode 1704 a may range from 0.05 cm to 1 cm,from 0.075 cm to 0.75 cm, and/or from 0.1 cm to 0.5 cm. Similar rangesmay apply to a distance between the second miniaturized electrode 1702 band the fourth miniaturized electrode 1704 b. In one embodiment, thedistance between the miniaturized electrodes of the first set 1702 maybe 1 cm and the distance between the miniaturized electrodes of opposingsets may be 0.1 mm.

A minimum distance between neighboring electrodes of opposing sets, suchas between the first miniaturized electrode 1702 a and the thirdminiaturized electrode 1704 a, and/or between the second miniaturizedelectrode 1702 b and the fourth miniaturized electrode 1704 b may berelated to a minimum distance at which capacitive coupling is preventedbetween the first set of miniaturized electrodes 1702 and the second setof miniaturized electrodes 1704. The greater the distance betweenneighboring electrodes of opposing sets, the less likely capacitivecoupling will occur. However, a maximum distance between neighboringelectrodes of opposing sets may be related to a distance greater thanthat at which a signal to noise ratio is less than or equal to 1. Thesmaller the distance between neighboring electrodes of opposing sets,the greater the signal to noise ratio may be. Accordingly, an optimaldistance between neighboring electrodes of opposing sets may be aminimum distance at which capacitive coupling is prevented.Additionally, a distance between the miniaturized electrodes of thesecond set 1704 may be greater than the distance between neighboringelectrodes of opposing sets. As described herein, a distance between theminiaturized electrodes of the first set may correspond to a depth towhich measurements may reach.

FIG. 17D illustrates interdigitated miniaturized electrodes, accordingto an embodiment. Some of the features in FIG. 17D are the same as orsimilar to some of the features in FIGS. 1-17C as noted by same and/orsimilar reference characters, unless expressly described otherwise. Inaddition to the first miniaturized electrode 1702 a and the secondminiaturized electrode 1702 b, the first set of miniaturized electrodes1702 may include the fifth miniaturized electrode 1702 c and the sixthminiaturized electrode 1702 d. In addition to the third miniaturizedelectrode 1704 a and the fourth miniaturized electrode 1704 b, thesecond set of miniaturized electrodes 1704 may include the seventhminiaturized electrode 1704 c and the eighth miniaturized electrode 1704d. The first set of miniaturized electrodes 1702 and the second set ofminiaturized electrodes may be interdigitated. Accordingly, oneminiaturized electrode of one set may be positioned between and adjacentto two miniaturized electrodes of the other set. For example, the thirdminiaturized electrode 1704 a may be positioned between and adjacent tothe first miniaturized electrode 1702 a and the fifth miniaturizedelectrode 1702 c, and so forth. Additionally, similar to the embodimentdepicted in FIG. 17C, a distance between the miniaturized electrodes ofthe second set 1704 may be greater than the distance between neighboringelectrodes of opposing sets.

Interdigitated electrodes may enable a user to select a depth to whichmeasurement may be taken. For example, for a first depth, the user mayselect as the voltage electrodes the third miniaturized electrode 1704 aand the fourth miniaturized electrode 1704 b, and as the currentelectrodes the fifth miniaturized electrode 1702 c and the sixthminiaturized electrode 1702 d. For a second depth, the user may selectas the voltage electrodes the seventh miniaturized electrode 1704 c andthe fourth miniaturized electrode 1704 b, and as the current electrodesthe first miniaturized electrode 1702 a and the fifth miniaturizedelectrode 1702 c. For a third depth, the user may select as the voltageelectrodes the seventh miniaturized electrode 1704 c and the eighthminiaturized electrode 1704 d, and as the current electrodes the firstminiaturized electrode 1702 a and the second miniaturized electrode 1702b. One or more of the miniaturized electrodes may be connected to aswitch between the miniaturized electrode and the current source or thevoltmeter. The user may select various of the miniaturized electrodesvia software, which may activate and/or deactivate the switch based on aselection by the user.

Interdigitated electrodes may enable a user to tune the signal to noiseratio based on a material and/or substance to be measured by theminiaturized electrodes. For example, noise may include impedance ofother tissue than a tissue of interest. Noise may include electricalsignals generated by the body. Noise may include harmonics from thesignal across the current electrodes. Noise may include capacitivecoupling, inductive coupling, internal current leakage of the circuitry,and so forth. As discussed above, capacitive coupling may be staved offby ensuring an appropriate spacing between miniaturized electrodes ofopposing sets. However, capacitive coupling may also be related to amaterial between the miniaturized electrodes. For a set of miniaturizedelectrodes with an air gap, a minimum spacing between adjacentminiaturized electrodes of opposing sets to prevent capacitive couplingmay range from 1 times an average height of the miniaturized electrodesto 3 times and average height of the miniaturized electrodes, from 1.5times an average height of the miniaturized electrodes to 2.5 times anaverage height of the miniaturized electrodes, or may be 2 times anaverage height of the miniaturized electrodes. In an embodiment, theminimum spacing between miniaturized electrodes of opposing sets toprevent capacitive coupling may be 2.5 times an average height of theminiaturized electrodes. However, as described herein, one or morevarious materials may be disposed between adjacent miniaturizedelectrodes of opposing sets, such as a polymer and/or tissue to bemeasured by the miniaturized electrodes. Accordingly, interdigitation ofthe miniaturized electrodes may allow for tuning of the spacing betweenadjacent miniaturized electrodes of opposing sets to minimize the effectof capacitive coupling and/or other noise.

FIG. 17E illustrates sets of miniaturized electrodes with interdigitatedfingers, according to an embodiment. Some of the features in FIG. 17Eare the same as or similar to some of the features in FIGS. 1-17D asnoted by same and/or similar reference characters, unless expresslydescribed otherwise. In various embodiments, miniaturized electrodes ofthe first set 1702 may be interconnected by electrode material, andminiaturized electrodes of the second set 1704 may be interconnected byelectrode material. For example, the first miniaturized electrode 1702 aand the fifth miniaturized electrode 1702 c may be interconnected byelectrode material, and so forth. The first miniaturized electrode 1702a and the fifth miniaturized electrode 1702 c may be fingers of thefirst set of miniaturized electrodes 1702, and so forth. Suchembodiments may have similar effects and/or features as those describedregarding the interdigitated miniaturized electrodes of FIG. 17D.Additionally, the sets of miniaturized electrodes with interdigitatedfingers depicted in FIG. 17E may allow for further enhancement of thesignal to noise ratio. The positioning of a finger of the second set ofminiaturized electrodes 1704 adjacent to and between two fingers of thefirst set of miniaturized electrodes 1702 may enhance an amount ofsignal detected by the second set of miniaturized electrodes 1704. Theproximity of the fingers of the opposing sets of miniaturized electrodesmay increase a ratio of signal to background noise relative to, forexample, an impedance sensor including pads which may cover a similarsurface area.

In one example, a miniaturized impedance sensor may include a row ofinterdigitated miniaturized electrodes alternating between aminiaturized electrode 1702 a or 1702 c of a first set of miniaturizedelectrodes 1702 and another miniaturized electrode 1704 a or 1704 c of asecond set of miniaturized electrodes 1704. In another example, a firstend miniaturized electrode 1702 a may be positioned at a first end ofthe row of interdigitated miniaturized electrodes and a second endminiaturized electrode 1704 a may be positioned at a second end of therow of interdigitated miniaturized electrodes. In another example, thefirst set of miniaturized electrodes and/or the second set ofminiaturized electrodes may include middle miniaturized electrodes 1702c and 1704 c adjacent to each other and positioned at a middle of therow of interdigitated miniaturized electrodes. In another example, thefirst set of miniaturized electrodes may transmit an electrical signaland the second set of miniaturized electrodes may receive the electricalsignal, or vice versa.

In one embodiment, a miniaturized electrode 1702 a-1702 d or 1704 a-1704d maybe a miniaturized electrode strip or a miniaturized electrodepillar. In one example, a contact surface of the miniaturized electrodestrip for contacting the body part may be formed by a length of theminiaturized electrode strip and a width of the miniaturized electrodestrip. In another example, a thickness of the miniaturized electrodestrip may extend from the band towards the body part as a user wears awearable device that the miniaturized electrode 1702 a-1702 d and/or1704 a-1704 d are integrated into. In another example, a contact surfaceof the miniaturized electrode pillar may include a dot defined by alength and a width of the miniaturized electrode pillar. In anotherexample, a height of the miniaturized electrode pillar is configured toextend from a band of a wearable device towards the body part as theuser wears the wearable device.

In another example, the first set of miniaturized electrodes 1702 or thesecond set of miniaturized electrodes 1704 comprises a forkedminiaturized electrode. The forked miniaturized electrode may includetwo strips 1702 a and 1702 c, 1702 b and 1702 d, 1704 a and 1704 c, or1704 b and 1704 d that extending parallel to the dermal layer of a bodypart. The two strips may be interconnected by an interconnecting stripof miniaturized electrode material. In another example, the first forkedminiaturized electrode may be positioned in the band to face an oppositedirection as the second forked miniaturized electrode such that thefirst forked miniaturized electrode and the second forked miniaturizedelectrode are interdigitated. In another example, the first set ofminiaturized electrodes 1702 forms a first circuit and the second set ofminiaturized electrodes 1704 forms a second circuit. The first circuitand the second circuit may be electronically isolated from each other inthe miniaturized impedance sensor. In another example, the first set ofminiaturized electrodes 1702 and the second set of miniaturizedelectrodes 1704 form a circuit via the body part in a miniaturizedimpedance sensor.

In another example, the first set of miniaturized electrodes 1702 maypass a current through the body part as the user wears the band and thesecond set of miniaturized electrodes 1704 measures an electric field inthe body part as the user wears the band. In another example, theminiaturized impedance sensor may include a row of interdigitatedminiaturized electrodes alternating between a miniaturized electrode ofa first set of miniaturized electrodes 1702 and another miniaturizedelectrode of a second set of miniaturized electrodes 1704. In anotherexample, a first electrode pad of the first set of miniaturizedelectrodes 1702 or the second set of miniaturized electrodes 1704 may besituated against the body part along a first plane and a secondelectrode pad of the first set of miniaturized electrodes 1702 or thesecond set of miniaturized electrodes 1704 may be situated against thebody part along a second plane. The first plane and the second planeintersect.

In another example, the first set of miniaturized electrodes 1702 or thesecond set of miniaturized electrodes 1704 may include a firstminiaturized electrode strip and a second miniaturized electrode strip.The first miniaturized electrode strip may be aligned approximatelyparallel to the second miniaturized electrode strip. The firstminiaturized electrode strip and the second miniaturized electrode stripmay be monolithically coupled to each other by an interconnecting strip.The interconnecting strip may be aligned approximately perpendicular tothe first miniaturized electrode strip and the second miniaturizedelectrode strip. In another example, the first set of miniaturizedelectrodes 1702 or the second set of miniaturized electrodes 1704 mayinclude a row of two or more miniaturized electrode pillars having agreater height than length or width. A contact surface of one of the twoor more miniaturized electrode pillars may include a dot defined by alength of the miniaturized electrode pillar and a width of theminiaturized electrode pillar. The miniaturized electrode pillar mayinclude the contact surface to contact the body part as the user wearsthe band. The miniaturized electrode pillar may extend towards the bodypart from the band as the user wears the band. In another example, a rowof interdigitated miniaturized electrodes may be positioned within aband of the wearable device and run parallel to a diameter of themuscular-walled tube as the user wears the band or run perpendicular tothe diameter of the muscular-walled tube as the user wears the band.

FIG. 17F illustrates interdigitated miniaturized electrodes betweenelectrode pads, according to an embodiment. Some of the features in FIG.17F are the same as or similar to some of the features in FIGS. 1-17E asnoted by same and/or similar reference characters, unless expresslydescribed otherwise. The first set of miniaturized electrodes 1702 mayadditionally include a first impedance pad 1702 e. The second set ofminiaturized electrodes 1704 may additionally include a second impedancepad 1702 e. The first impedance pad 1702 e and/or the second impedancepad 1704 e may have surface areas ranging from 0.5 cm² to 2 cm². Thefirst impedance pad 1702 e and the second impedance pad 1704 e may bepositioned on opposite sides of the other miniaturized electrodes. Invarious embodiments, placing the first impedance pad 1702 e along anopposite side of the artery 1714 from the second impedance pad 1704 emay allow a user to tune an impedance measurement to the artery 1714,eliminating noise such as background noise, physiological noise, and soforth.

FIG. 18 illustrates a controls schematic for a bioimpedance circuit1800, according to an embodiment. Some of the features in FIG. 18 arethe same as or similar to some of the features in FIGS. 1-17E as notedby same and/or similar reference characters, unless expressly describedotherwise. The bioimpedance circuit 1800 may include a microcontroller1802 (MCU 1802), a digital-to-analog converter 1804 (DAC 1804), avoltage-to-current converter 1806 (V to I 1806), a first miniaturizedelectrode 1808, a second miniaturized electrode 1810, a thirdminiaturized electrode 1812, a fourth miniaturized electrode 1814, anoperational amplifier 1816 (op amp 1816), a first analog-to-digitalconverter 1818 (first ADC 1818), a second analog-to-digital converter1820 (second ADC 1820), a first bandpass filter 1822 (first BPF 1822), asecond bandpass filter 1824 (second BPF 1824), a signal mixer 1826, anda low pass filter 1828 (LPF 1828). In an embodiment, one or more of thefirst miniaturized electrode 1808, the second miniaturized electrode1810, the third miniaturized electrode 1812, and the fourth miniaturizedelectrode 1814 may be the same as or similar to the miniaturizedelectrode 412 described and/or illustrated throughout this disclosure.The bioimpedance circuit 1800 may be implemented for generating signalsto measure physiological characteristics, detecting the resultingsignals, and transmitting the signals to a processing device.

In an embodiment, the MCU 1802 may pass an electronic signal 1830 to theDAC 1804. After the DAC 1804, the electronic signal 1830 may be split. Aportion of the electronic signal 1830 may be directed to the first ADC1818, and a portion of the electronic signal 1830 may be directed to theV to I 1806. The portion of the electronic signal 1830 passed to thefirst ADC 1818 may have a first voltage measurement matching an outputvoltage of the DAC 1804. The V to I 1806 may convert the output voltageof the DAC 1804 to a current. In an embodiment, the current may be 500microamps pulsing at a frequency of 8 kHz. The current may be passedfrom the V to I 1806, through the first miniaturized electrode 1808,through an impeding substance 1832, through the second miniaturizedelectrode 1810, and back into the V to I 1806. The third miniaturizedelectrode 1812 and the fourth miniaturized electrode 1814 may bedisposed against the impeding surface 1832 between the firstminiaturized electrode 1808 and the second miniaturized electrode 1810.In an embodiment, the first miniaturized electrode 1808 and the secondminiaturized electrode 1810 may be part of a first set of miniaturizedelectrodes. The first set of miniaturized electrodes may be similar tothe first set of miniaturized electrodes 1702 described and/orillustrated regarding FIGS. 17A-B, and/or may include the miniaturizedelectrodes 412 described and illustrated throughout this disclosure. Inan embodiment, the third miniaturized electrode 1812 and the fourthminiaturized electrode 1814 may be part of a second set of miniaturizedelectrodes. The second set of miniaturized electrodes may be similar tothe second set of miniaturized electrodes 1704 described and/orillustrated regarding FIGS. 17A-B, and/or may include the miniaturizedelectrodes 412 described and illustrated throughout this disclosure.

The second set of miniaturized electrodes may be electrically coupled tothe op amp 1816. In an embodiment, the op amp 1816 may include acomparator. The op amp 1816 may output a voltage to the second ADC 1820based on a voltage difference between the third miniaturized electrode1812 and the fourth miniaturized electrode 1814. The first ADC 1818 andthe second ADC 1820 may convert the input from analog to digitalsignals. The digital signals may be passed to the first BPF 1822 and thesecond BPF 1824, respectively. The digital signals may be combined intoa single signal by the signal mixer 1826, passed through the LPF 1828,and then passed to a processing device for calculation impedance andcorrelation with a physiological condition, physiological parameter,and/or physiological constituent.

FIG. 19 illustrates a heartbeat waveform 1900 as measured by aminiaturized impedance sensor such as the miniaturized impedance sensor400, according to an embodiment. In one example, a structure of a bodypart of a user, such as a muscular-walled tube, may include a dynamicinternal feature which causes a variability in an impedance of thestructure. The dynamic internal feature may include a variable volume ormaterial constituency, such as an amount of blood in the muscular-walledtube or a diameter or size of the muscular-walled tube.

The heartbeat waveform 1900 may be used by a processing device toisolate and/or identify a physiological condition, a physiologicalparameter, and/or a physiological constituent of a user of a wearabledevice such as the wearable device 100. A biometric impedancemeasurement 1902 may fluctuate over a variety of timeframes. Thetimeframes may include a first timeframe 1904, a second timeframe 1906,and a third timeframe 1908. The biometric impedance measurement 1902 maycorrespond to a change in a volume of blood within a body part adjacentto the miniaturized impedance sensor. The body part may include amuscular-walled tube for carrying blood, such as a vein or artery. Thebiometric impedance measurement 1902 may represented as a change involtage. As the volume of blood within the body part increases, thevoltage measured by the miniaturized impedance sensor may increase. Asthe volume of blood within the body part decreases, the voltage measuredby the miniaturized impedance sensor may decrease. A shape of theheartbeat waveform 1900 may include noise 1910. The noise may correspondto one or more other physiological and/or non-physiological factors suchas feedback and/or electronic noise within the miniaturized impedancesensor, electrical signals within the body not generated by theminiaturized impedance sensor, and so forth.

Voltage changes within the various timeframes may correspond in time tochanges in physiological features that may effect a volume of blood inthe user's vein and/or artery. For example, a short timeframe such asthe first timeframe 1904 may correspond to the user's heartbeat and/orbreathing. Viewing a shorter timeframe may illuminate one or more heartconditions, such as an effectiveness of a mitral valve of the heart asindicated by a dicrotic notch 1912. A longer timeframe such as thesecond timeframe 1906 may correspond to a sympathetic response of theuser or a posture change of the user. One such sympathetic response mayinclude vasoconstriction due to the user being exposed to cold. One suchposture change may include the user lowering the body part relative tothe user' heart and/or raising the body part relative to the user'sheart. The longer timeframe may correspond to the user performing aValsalva maneuver, such as when lifting weights. A yet longer timeframesuch as the third timeframe 1908 and timeframes longer than the thirdtimeframe 1908 may provide indication of a peripheral disease which mayeffect volumetric flow of blood and/or an amount of current impeded bythe blood. For example, increased levels of blood glucose may decreasethe impedance of the blood. Sustained levels of decreased impedance mayindicate glucose is not being removed from the blood sufficiently.Excess blood glucose may lead to one or more of a number of healthconditions, such as blood vessel damage, organ damage, and so forth.

During the first timeframe 1904, the voltage of the measurement may varyby as much as 3×10⁻⁵ Volts (V) over approximately 3 seconds. A localmaximum within the first timeframe 1904 may correspond to the user'sheart contracting, forcing blood out of the heart and through the arteryand/or vein. A local minimum within the first timeframe 1904 maycorrespond to the user's heart expanding and drawing blood from theartery and/or vein. During the second timeframe 1906, the voltage of themeasurement may vary by as much as 6×10⁻⁵ V over approximately 10seconds. The second timeframe 1906 may correspond to a physiologicalcondition, physiological parameter, and/or physiological constituentclosely related to the user's heartbeat. A relative increase of thelocal maximums and/or the local minimums may correspond to, for example,vasodilation. During the third timeframe 1908, the voltage of themeasurement may vary by as much as 1×10⁻⁴ V over approximately 25seconds. The third timeframe 1908 may correspond to a physiologicalcondition, physiological parameter, and/or physiological constituentunrelated to the user's heartbeat, such as a hydration condition of theuser. Longer timeframes may correspond to more a static physiologicalcondition, physiological parameter, and/or physiological constituent ofthe user, such as body fat percentage and/or bone density.

The biometric impedance measurement 1902 may be passed to a processingdevice which may perform a function on the heartbeat waveform 1900 toseparate constituent waveforms of the heartbeat waveform 1900. Thefunction may include, for example, a regression analysis. The processingdevice may identify a timeframe associated with an individualconstituent waveform to identify a type of physiological condition,physiological parameter, and/or physiological constituent to which theconstituent waveform corresponds. In an embodiment, the processingdevice may select constituent waveforms on a timeframe corresponding tothe user's heartbeat to determine physiological constituent of theuser's blood. In an embodiment, the processing device may selectconstituent waveforms on a timeframe much larger than a timeframe of theuser's heartbeat to determine a physiological condition of the user'sskin. In an embodiment, the processing device may select a constituentwaveform based on a shape of succeeding crests and valleys. The shape ofsucceeding crests and valleys may correspond to one or more of adiastole, a systole, and a dichroic notch of the user's heartbeat.

In an embodiment, the wearable device 100 may include a=the band 106,the user interface 104, the miniaturized impedance sensor 400, theprocessing device 102, and the electrical circuit 108. The band 106 maybe configured to extend at least partially around the body part 320 of auser, the body part 320 comprising the dermal layer and themuscular-walled tube 322 or 324 within the body part 320. The userinterface 104 may be coupled to the band 106. The electrical circuit 108may be embedded in the band 106. The electrical circuit 108 mayinterconnect the user interface 104, the processing device 102, or theminiaturized impedance sensor 400.

The miniaturized impedance sensor 400 may be integrated into the band106 and positioned in the band 106 to be pressed against the dermallayer and straddle the muscular-walled tube 322 or 324 when the userwears the band 106. The miniaturized impedance sensor 400 may include afirst set of the miniaturized electrodes 412 and a second set of theminiaturized electrodes 412. The first set of the miniaturizedelectrodes 412 may include a first miniaturized electrode 412 and asecond miniaturized electrode 412. The second set of the miniaturizedelectrodes 412 may include a third miniaturized electrode 412 and afourth miniaturized electrode 412. The first miniaturized electrode 412and the second miniaturized electrode 412 may straddle the thirdminiaturized electrode 412 and the fourth miniaturized electrode 412.The first set of the miniaturized electrodes 412 may be configured togenerate a signal, the signal having a property that is variable basedon a variable state of the muscular-walled tube 322 or 324. The secondset of the miniaturized electrodes 412 may be configured to measure theproperty of the signal.

The processing device 102 may be configured to interrogate themuscular-walled tube 322 or 324 via the miniaturized impedance sensor400. The processing device 102 may be configured to generate the signalby the first set of the miniaturized electrodes 412. The signal may beconfigured to pass through the muscular-walled tube 322 or 324 as theuser wears the band. The processing device 102 may be configured to takea set of measurements, by the second set of the miniaturized electrodes412, over a period of time as the user wears the band 106. Theprocessing device 102 may be configured to determine the heartbeatwaveform 1900 of the user based on the set of measurements. Theprocessing device 102 may be configured to determine a change in acondition of the user, the body part 320, or the muscular-walled tube322 or 324 based on a change in the heartbeat waveform 1900.

In one example of the embodiment, the heartbeat waveform 1900 mayinclude a local peak corresponding to a cardiac diastole as a heart ofthe user fills with blood. The heartbeat waveform 1900 may include alocal valley corresponding to a ventricular systole as the blood isforced from the heart into the muscular-walled tube. The heartbeatwaveform 1900 may include the dicrotic notch 1912 between the localvalley and the local peak corresponding to a closure of the backflowvalve of the heart.

In another example of the embodiment, the heartbeat waveform 1900 mayinclude changes in the heartbeat waveform 1900 over the first timeframe1904 and the second timeframe 1906. The first timeframe 1904 maycorrespond to a change in a first condition of the muscular-walled tube322 or 324 or material within the muscular-walled tube 322 or 324. Thesecond timeframe 1906 may be longer than the first timeframe 1904. Thesecond timeframe 1906 may correspond to a change in a second conditionof the muscular-walled tube 322 or 324 or material within themuscular-walled tube 322 or 324. The first condition or the secondcondition may include a change in shape, a change in volume, or a changein material content of the muscular-walled tube 322 or 324 or thematerial within the muscular-walled tube 322 or 324.

In an example, the property of the signal may include an electromagneticproperty of the signal. The variable state of the muscular-walled tube322 or 324 may include a change in a shape, a volume, or a materialcontent of the muscular-walled tube 322 or 324 over a period of time.The processing device 102 may be configured to filter noise out of thesignal based on the heartbeat waveform 1900. The noise may includechanges in the signal over a noise timeframe. The heartbeat waveform1900 may include a heartbeat timeframe ranging from one quarter of asecond to two seconds. The noise timeframe may be less than theheartbeat timeframe.

In another example, the change in the condition may include a change ina volume of blood within the muscular-walled tube 322 or 324. The changein the volume may be caused by a pressure wave within themuscular-walled tube 322 or 324. The pressure wave within themuscular-walled tube 322 or 324 may be caused by the heart of the userpumping the blood through the muscular-walled tube 322 or 324. Thechange in the volume of the blood may change an impedance measured bythe miniaturized impedance sensor 400 as the user wears the band 106.The change in the condition may include a change in an amount of glucosewithin the muscular-walled tube 322 or 324. The change in the amount ofglucose may change an impedance measured by the miniaturized impedancesensor 400 as the user wears the band 106.

In an embodiment, the miniaturized impedance sensor 400 may beelectronically coupled to the processing device 102. The miniaturizedimpedance sensor 400 may be coupled to a dermal layer of the body part320. The body part 320 may include a subdermal feature such as bone,ligament, or the muscular-walled tube 322 or 324. The miniaturizedimpedance sensor 400 may include a first miniaturized electrode 412, asecond miniaturized electrode 412, a third miniaturized electrode 412,and a fourth miniaturized electrode 412. The first miniaturizedelectrode 412 and the second miniaturized electrode 412 may straddle thethird miniaturized electrode 412 and the fourth miniaturized electrode412. The first miniaturized electrode 412 and the second miniaturizedelectrode 412 may be configured to generate a signal. The thirdminiaturized electrode 412 and the fourth miniaturized electrode 412 maybe configured to measure the signal.

The processing device 102 may be configured to generate the signal bythe first miniaturized electrode 412 and the second miniaturizedelectrode 412. The signal may pass through the subdermal feature. Theprocessing device 102 may be configured to measure the signal by thethird miniaturized electrode 412 and the fourth miniaturized electrode412. The processing device 102 may be configured to determine animpedance of the subdermal feature based on the measurement of thesignal. The processing device 102 may be configured to map a change inthe impedance from a measurement taken at a previous time. Theprocessing device 102 may be configured to generate the heartbeatwaveform 1900 based on the change in the impedance.

In an example of the embodiment, the measurement may include a firstindicator corresponding to a first condition and a second indicatorcorresponding to a second condition. The first indicator may berepresented within the second indicator in the heartbeat waveform 1900.The second indicator may be discernable from the first indicator byperforming a regression analysis on the heartbeat waveform 1900. Thesubdermal feature may include the muscular-walled tube 322 or 324carrying blood. The first indicator may correspond to a pressure waveradiating through the muscular-walled tube 322 or 324. The secondindicator may correspond to a constriction or a dilation of themuscular-walled tube 322 or 324. The miniaturized impedance sensor 400may measure the pressure wave and the constriction or the dilation asthe miniaturized impedance sensor 400 is coupled to the body part. Theprocessing device 102 may be configured to perform the regressionanalysis by averaging peaks and valleys of the heartbeat waveform 1900corresponding to the first indicator. The second indicator maycorrespond to a change across a plurality of averages of the peaks andthe valleys.

In another example, the change in the impedance may correspond to achange in a volume of the subdermal feature. The change in the volumemay cause an increase in the impedance. A change in a constituentmaterial of the subdermal feature may cause an increase in the impedanceor a decrease in the impedance. The change in the constituent materialmay occur over a longer timeframe than the change in the volume. Theprocessing device may be configured to identify the change in the volumefrom the change in the constituent material based on determining whetherthe change in the impedance occurs over the longer time frame.

In yet another embodiment, the miniaturized impedance sensor 400 may beconfigured to take a measurement from the muscular-walled tube 322 or324 within a body part 320 of the user. The miniaturized impedancesensor 400 may include a first set of the miniaturized electrodes 412and second set of miniaturized electrodes 412. The first set of theminiaturized electrodes 412 may be configured to generate a signalwithin the muscular-walled tube 322 or 324. The second set of theminiaturized electrodes 412 may be configured to measure the signal, themeasurement taken from the muscular-walled tube 322 or 324. Theembodiment may include the processing device 102, which may beprogrammed to interrogate the muscular-walled tube 322 or 324 via theminiaturized impedance sensor 400. The processing device 102 may beconfigured to generate the signal by the first set of the miniaturizedelectrodes 412. The processing device 102 may be configured to measurethe signal by the second set of miniaturized electrodes 412. Theprocessing device 102 may be configured to generate the heartbeatwaveform 1900 based on the measurement of the signal by the second setof the miniaturized electrodes 412. The processing device 102 may beconfigured to determine a condition of the user based on the heartbeatwaveform 1900.

In one example of the embodiment, the processing device 102 may beconfigured to correlate a change in the measurement with a change in: aposture of the body part; a sympathetic response of the body part; or aVal Salva maneuver by the user. The change in the measurement may occurover a timeframe of less than one minute. The processing device 102 maybe configured to correlate a change in the measurement with a change inglucose in the muscular-walled tube or a change in a hydration conditionof the user.

In another example, the heartbeat waveform 1900 may include a firstpattern indicating a first condition of the user and a second patternindicating a second condition of the user. The first pattern may berepresented within the second pattern in the heartbeat waveform 1900.The processing device 102 may be configured to take a first set ofmeasurements using the miniaturized impedance sensor 400. The processingdevice 102 may be configured to generate the heartbeat waveform 1900based on the first set of measurements. The processing device 102 may beconfigured to take a second set of measurements using a second sensorsuch as the first sensor 112. The second set of measurements may form asecond waveform which may include the second pattern. The processingdevice 102 may be configured to isolate the first pattern from theheartbeat waveform 1900 by comparing the heartbeat waveform 1900 to thesecond waveform to identify the second pattern in the heartbeat waveform1900.

In yet another example, the processing device 102 may be configured toindex a change in the measurement to a passage of time. The passage oftime may correspond to changes in two conditions of the user. Theprocessing device 102 may be configured to filter noise from theheartbeat waveform. The noise may include a change in the heartbeatwaveform 1900 over a first timeframe. The first timeframe may be shorterthan a minimum timeframe between a local valley and a local peak of theheartbeat waveform 1900 corresponding to a heartbeat of the user.

FIGS. 20-24 depict various methods for making, manufacturing, and/orpreparing a miniaturized impedance sensor such as the miniaturizedimpedance sensor 400, according to various embodiments. The steps of themethods are illustrated in the figures as blocks. Although an order maybe inferred from the illustrations and/or from the accompanyingdescriptions, the order is not intended to limit the scope of themethods to the particular orders of the steps that may be inferred.Various steps of the methods may be done out of order, in a differentorder, and/or may be omitted without departing from the substance and/orspirit of this disclosure. For example, two blocks may be described in aparticular sequence in this disclosure but may be performed in anopposite sequence without altering the method in any substantial and/ormaterial way.

Methods and/or techniques described throughout this disclosure maygenerally refer to “depositing,” “growing,” and/or “patterning.” As usedthroughout this disclosure, “deposit” and/or “grow,” including semanticand/or stemmed variations of “deposit” and/or “grow,” may refer to anyof a variety of processes used for layering material. In one embodiment,a first layer may be deposited on a second layer by forming the firstlayer and then placing the first layer on the second layer. In anotherembodiment, the first layer may be deposited on the second layer by athin film deposition technique. The thin film deposition technique mayinclude physical vapor deposition (PVD), cathodic arc deposition,electron beam PVD, electron beam evaporation, chemical vapor deposition(CVD), atomic layer deposition, close-space sublimation, sputterdeposition, pulsed electron deposition, sublimation sandwich deposition,and so forth. In an embodiment, the first layer may be deposited on thesecond layer by a thin film growth mode such as Frank-van de Merwegrowth, Stranski-Krastanov growth, Volmer-Weber growth, epitaxialgrowth, and/or molecular beam epitaxy. In an embodiment, the first layermay be deposited on the second layer by a sputtering method such asdiode sputtering, radio frequency sputtering, magnetron sputtering,and/or reactive sputtering.

As used throughout this disclosure, “pattern,” including semantic and/orstemmed variations of “pattern,” may refer to a structure and/or orderof sections of an individual layer. A patterned layer may have two ormore sections and/or regions of various thickness and/or shape. Forexample, a first section of the layer may have a first thickness, and asection of the layer may have a second thickness that may be greaterthan or less than the first thickness. A first shape of the firstsection of the layer may be the same as or different than a second shapeof the second section of the layer. In an embodiment, a pattern of thelayer may be geometric, tiled, spiraled, meandering, waving, foamy,cracked, symmetric, asymmetric, reflective, chaotic, fractal, and soforth.

As used throughout this disclosure, “coat,” including semantic and/orstemmed variations of “coat,” may refer to any of a variety of processesfor coating an object with a thin film. The thin film may be of uniformthickness or variable thickness. The thickness may vary from less than 1micron to 5 mm. The processes may include spin coating, spray coating,dip coating, roller coating, and/or sputtering.

FIG. 20 illustrates a method 2000 of preparing a miniaturized impedancesensor, according to an embodiment. The method 2000 may includepatterning a conductive layer, such as the conductive layer 406, on asensor substrate (block 2004). The conductive layer may be patterned onthe sensor substrate using a deposition technique such as PVD.

In various embodiments the deposition technique may include sputteringand/or evaporation. The pattern may include one or more of the patternsdescribed and/or illustrated herein. The sensor substrate may include agrowth substrate such as the growth substrate 402 and a base insulatinglayer such as the first insulating layer 404. In various embodimentswhere the conductive layer may include nickel and the sensor substratemay include silicon, the base insulating layer may prevent formation ofnickel silicide. The method 2000 may include depositing a medialinsulating layer, such as the second insulating layer 408, on theconductive layer (block 2006). In one embodiment, the medial insulatinglayer may be deposited over positive and negative regions of theconductive layer. In another embodiment, the medial insulating layer maybe patterned. The pattern of the medial insulating layer may alignpositive regions of medial insulating layer material on positive regionsof the conductive layer. In one example, a first insulating layer may bedisposed on the growth substrate. The first insulating layer may preventmolecular reaction of a deposition material with the growth substrateduring a PVD process or a CVD process. In one example, the growthsubstrate may withstand infiltration at a threshold temperature for aphysical vapor deposition (PVD) process or a chemical vapor deposition(CVD) process.

The method 2000 may include patterning a catalyst layer, such as thecatalyst layer 410, on the medial insulating layer (block 2008). Thecatalyst layer may be patterned similarly to the medial insulating layerso that positive regions of the catalyst layer may be aligned onpositive regions of medial insulating layer and/or positive regions ofconductive layer. The catalyst layer may be deposited on the medialinsulating layer by sputtering, evaporation, and so forth. The method2000 may include growing miniaturized electrodes, such as theminiaturized electrodes 412, on the catalyst layer (block 2010). In oneexample, the second insulating layer 408 may be rendered conductive byan environmental condition for growth of the miniaturized electrode onthe catalyst layer. The medial insulating layer may be deposited viasputtering, evaporation, and so forth. The environmental condition thatrenders the second insulating layer may include a temperature, apressure, or a time frame of the PVD process or the CVD process.

In various embodiments, the miniaturized electrodes may be grown viachemical vapor deposition (CVD). The method 2000 may includeinfiltrating the miniaturized electrodes with a bolstering material,such as the bolstering material described regarding FIGS. 4A-C (block2012). The miniaturized electrodes may be infiltrated with thebolstering material via CVD. The method 2000 may include applying ahydrophilic treatment to the miniaturized electrodes to render theminiaturized electrodes hydrophilic (block 2014). For example, in oneembodiment, the miniaturized electrodes may include carbon-infiltratedCNTs. Applying the hydrophilic treatment may include exposing thecarbon-infiltrated CNTs to Ozone. The CNTs may be placed in a tubehaving a 6.5 cm² cross-section and ozone may be flowed over the CNTs atroom temperature for 30 minutes at a rate of 4.4 grams/hour.

The method 2000 may include coating the growth substrate, the conductivelayer, the medial insulating layer, the catalyst layer, and/or theminiaturized electrodes with an interstitial filler such as theinterstitial filler 414 (block 2016). For example, the interstitialfiller may include polyimide. The growth substrate, the conductivelayer, the medial insulating layer, the catalyst layer, and/or theminiaturized electrodes may be coated with the polyimide by spinningand/or spraying the polyimide over the layers. The method 2000 mayinclude removing a portion of the interstitial filler to expose topportions of the miniaturized electrodes (block 2018). For example, thepolyimide may be subjected to photo exposure to a partial depth of thepolyimide. The photo exposure may degrade the exposed polyimide. Thedegraded polyimide may be washed away in a chemical bath to expose thetop portions of the miniaturized electrodes. In another example, aportion of the interstitial filler may be removed by polishing theinterstitial filler. The method 2000 may include applying a treatment tothe interstitial filler to render the interstitial filler insolventand/or solvent resistant (block 2020). For example, the polyimide may becross-linked by heating the polyimide or via UV exposer of thepolyimide. The method 2000 may include inducing reflow of theinterstitial filler (block 2022). For example, the coated layers may beplaced in a heating chamber. The temperature of the heating chamber maybe slowly increased to a cross-linking temperature of the interstitialfiller, such as over 1 minute, 2 minutes, 5 minutes, and/or 10 minutes.The increasing temperature may melt the interstitial filler, therebyinducing reflow of the interstitial filler. The reflow may causeportions of the interstitial filler to slope up the miniaturizedelectrodes, creating wells, such as the wells 414 a and 414 b, in theinterstitial filler between neighboring miniaturized electrodes.

The method 2000 may include scoring and/or partially dicing through oneor more layers, including the sensor substrate, the medial insulatinglayer, and/or the interstitial filler (block 2024). For example, thesensor substrate may include a silicon wafer having a layer of alumina.A plurality of miniaturized impedance sensors may be formed on and/orincorporating the sensor substrate, according to an embodiment. Thesensor substrate, the medial insulating layer, and/or the interstitialfiller may be common among the plurality of miniaturized impedancesensors. The miniaturized impedance sensors may be separated from eachother by scoring and/or partially dicing the one or more layers toseparate the miniaturized impedance sensors. The scoring may beperformed from the substrate-side of the miniaturized impedance sensor.The scoring and/or dicing may be aligned with areas of the baseinsulating material. This may prevent accidental cutting of theminiaturized electrodes. In various embodiments, the sensor substratemay be diced to separate the miniaturized impedance sensors. In variousembodiments, the sensor substrate may be scored. The scoring mayincrease a surface area which may be exposed to allow for quicker and/oreasier release of the miniaturized impedance sensor from the sensorsubstrate. In one example, the substrate may be diced to segregatesubsets of an array of miniaturized electrodes while the interstitialfiller between the subsets remains intact, to allow the miniaturizedimpedance sensor to flex between the subsets.

The method 2000 may include releasing the sensor substrate from theother layers (block 2026). For example, the miniaturized impedancesensor, including the sensor substrate and the other layers depositedthereon, may be submersed in a chemical bath such as potassium hydroxide(KOH). The KOH may etch the base insulating layer to release theminiaturized electrodes and conductive layer from the sensor substrate.In an embodiment, after releasing the sensor substrate, some of the baseinsulating layer may remain attached to one or more of the conductivelayer, the medial insulating layer, the catalyst layer, the miniaturizedelectrodes, and/or the interstitial filler. Accordingly, the method 2000may include etching the layers to remove the base insulating layerand/or a process byproduct (block 2028). For example, a layer of aluminamay remain after the silicon wafer is released. The alumina may beremoved by plasma etching and/or wet etching such as a chemical bath. Inanother example, various of the processes the conductive layer may besubjected to during the process of preparing the miniaturized impedancesensor may expose the conductive layer to high heat and/or chemicalswhich may catalyze the oxidation of the conductive, according to anembodiment. The oxidized nickel may be removed by plasma etching and/orsolder flux. In an embodiment, the remaining layers, including theconductive layer, the medial insulating layer, the catalyst layer, theminiaturized electrodes, and/or the interstitial filler may form anembodiment of a miniaturized impedance sensor, such as the miniaturizedimpedance sensor 400.

In various embodiments, the miniaturized impedance sensor may beimplemented in one or more of a variety of ways as described and/orillustrated throughout this disclosure. The method 2000 may includeplacing the miniaturized impedance sensor onto a device substrate, suchas the substrate 816, for incorporating the miniaturized impedancesensor into a wearable device such as the wearable device 100 (block2030). The device substrate may include a flexible substrate. Thesubstrate may in an embodiment, include polyimide. In an embodiment, thesubstrate may include a pattern of electrical leads. The pattern maymatch a pattern of the conductive layer. The miniaturized impedancesensor may be adhered to the device substrate by applying an adhesive tothe device substrate and/or a conductive layer side of the miniaturizedimpedance sensor and then placing the miniaturized impedance sensor andthe device substrate together. The adhesive may include a solder paste,according to an embodiment. In various embodiments, the miniaturizedimpedance sensor may be adhered to the device substrate by applying aconductive epoxy and/or heat activated conductive adhesive. The devicesubstrate may include patterned leads. The leads may be patterned on thedevice substrate to match the pattern of the conductive layer. Theminiaturized impedance sensor and the device substrate may be joined sothat the conductive layer contacts the patterned leads. The adhesive maysecure the miniaturized impedance sensor and the device substratetogether. Securing the miniaturized impedance sensor and the devicesubstrate with the adhesive may include activating the adhesive. In anembodiment, the adhesive may include solder and activating the adhesivemay include heating the solder to induce reflow. In various embodiments,a plurality of miniaturized impedance sensors may be joined to a singlesheet of device substrate. Accordingly, the method 2000 may includecutting the device substrate to separate the miniaturized impedancesensors (block 2032).

FIG. 20B illustrates a sub-method of block 2030 in the method 2000 ofpreparing the nano impedance sensor, including placing miniaturizedelectrodes on a device substrate, according to an embodiment. Some ofthe blocks in FIG. 20B are the same as or similar to some of the blocksin FIGS. 1-20A as noted by same and/or similar reference characters,unless expressly described otherwise. The sub-method may include pickinga miniaturized electrode from a substrate (block 2030 a). Theminiaturized electrode may have been grown on the substrate such thatthe substrate is a growth substrate. The miniaturized electrode may bepicked from the substrate by tweezers. The sub-method may includepreparing a device substrate with an adhesive (block 2030 b). The devicesubstrate may include a surface to which the miniaturized electrode ismounted. Adhesive may be applied to the surface. The surface may includeone or more vias. The vias may include slots passing through the devicesubstrate. The slots may enable electrical connection of a wire from anunderside of the device substrate to the miniaturized electrode.

The sub-method may include placing the miniaturized electrode on thedevice substrate over one of the vias and on the adhesive (block 2030c). The adhesive may adhere the miniaturized electrode to the devicesubstrate. In an embodiment, the adhesive may be placed to avoid seepinginto the vias, leaving the vias clear for electrical connection. Thesub-method may include placing a wire along a back side of the devicesubstrate aligned with the via the miniaturized electrode is alignedover and soldering the wire to the device substrate and/or theminiaturized electrode (block 2030 d). In various embodiments, thedevice substrate may include a loop over the via along the back side ofthe device substrate, the loop positioned to receive the wire and holdthe wire in place as the wire is soldered to the device substrate and/orthe miniaturized electrode.

FIG. 21 illustrates a method 2100 of preparing the nano impedancesimilar to the method illustrated in FIG. 20A, including a single stepfor depositing multiple layers, according to an embodiment. Some of theblocks in FIG. 21 are the same as or similar to some of the blocks inFIGS. 1-20B as noted by same and/or similar reference characters, unlessexpressly described otherwise. The method 2100 may include depositing aconductive layer, a medial insulating layer, and a catalyst layer on thesensor substrate via an all-in-one deposition step (block 2104). In anembodiment, the conductive layer, the medial insulating layer, and/orthe catalyst layer may be patterned on the sensor by electron beamphysical vapor deposition, sputtering deposition, and so forth. Themethod 2100 may include depositing a medial insulating layer, such asthe second insulating layer 408, on the conductive layer (block 2006).The method 2100 may include patterning a catalyst layer, such as thecatalyst layer 410, on the medial insulating layer (block 2008). Themethod 2100 may include growing miniaturized electrodes, such as theminiaturized electrodes 412, on the catalyst layer (block 2010). Themethod 2100 may include infiltrating the miniaturized electrodes with abolstering material, such as the bolstering material described regardingFIGS. 4A-C (block 2012). The method 2100 may include applying ahydrophilic treatment to the miniaturized electrodes to render theminiaturized electrodes hydrophilic (block 2014). The method 2100 mayinclude coating the growth substrate, the conductive layer, the medialinsulating layer, the catalyst layer, and/or the miniaturized electrodeswith an interstitial filler such as the interstitial filler 414 (block2016). The method 2100 may include removing a portion of theinterstitial filler to expose top portions of the miniaturizedelectrodes (block 2018). The method 2100 may include applying atreatment to the interstitial filler to render the interstitial fillerinsolvent and/or solvent resistant (block 2020). The method 2100 mayinclude inducing reflow of the interstitial filler (block 2022).

In various embodiments, sensor substrate, the conductive layer, themedial insulating layer, the catalyst layer, the miniaturized electrode,and/or the interstitial filler may form a miniaturized impedance sensorsuch as the miniaturized impedance sensor 400. In an embodiment, aplurality of miniaturized impedance sensors may be formed together onthe same sensor substrate. Accordingly, the method 2100 may includescoring and/or cutting through one or more layers of the plurality ofminiaturized impedance sensors (block 2106). The scoring and/or cuttingmay be performed, in one embodiment, with a silicon wafer dicing saw.One or more individual miniaturized impedance sensors may be brokenand/or cut away from the plurality of miniaturized impedance sensors.The method 2100 may include integrating the individual miniaturizedimpedance sensor into a wearable device such as the wearable device 100.In an embodiment, a conductive material may be added to the miniaturizedimpedance sensor electrically coupled to the conductive layer. Theconductive material may be electrically coupled to various electronicsof the wearable device, such as on a circuit board via an electricaltrace. The electronics may be the same as or similar to the electroniccomponents 1206. The electronics may be interconnected via the circuitboard. The electrical trace may be the same as or similar to theelectrical trace 820. In one embodiment, the circuit board may be aflexible band of the wearable device, such as the band 106. Theelectrical trace, the electronics, and/or the miniaturized impedancesensor may be embedded in the band.

In addition or alternative to the blocks show in FIG. 21 , the method2100 may include: patterning a thin film conductive layer on a sensorsubstrate, where the sensor substrate includes a base insulating layerthat may prevent infiltration of a material into the sensor substrateand the thin film conductive layer may be deposited on the baseinsulating layer; depositing a thin film medial insulating layer on thethin film conductive layer; patterning a thin film catalyst layer on thethin film medial insulating layer to form a catalyst layer pattern, thecatalyst layer pattern being aligned with a conductive layer pattern;growing a nanotube miniaturized electrode on the thin film catalystlayer, the nanotube miniaturized electrode being aligned with a sectionof the catalyst layer pattern; infiltrating the nanotube miniaturizedelectrode with a bolstering material to bolster nanotubes of thenanotube miniaturized electrode; applying a hydrophilic treatment torender the nanotube miniaturized electrode hydrophilic; coating thenanotube miniaturized electrode with an interstitial filler toelectrically insulate the nanotube miniaturized electrode and bolsterthe nanotube miniaturized electrode; removing a top portion of theinterstitial filler to expose a top surface of the nanotube miniaturizedelectrode; cross-linking the interstitial filler to render theinterstitial filler solvent-resistant; inducing reflow of theinterstitial filler by increasing a temperature of the interstitialfiller from a first temperature at which the interstitial filler may besolid to a second temperature for melting point of the interstitialfiller, the temperature increasing to the melting point in 1 minute to 2minutes, 2 minutes to 5 minutes, or 5 minutes to 10 minutes; scoring ordicing the sensor substrate, the thin film medial insulating layer, orthe interstitial filler; releasing the sensor substrate or the baseinsulating layer from one or more sensor layers, wherein the one or moresensor layers includes the thin film conductive layer, the thin filmmedial insulating layer, the thin film catalyst layer, the nanotubeminiaturized electrode, or the interstitial filler; and/or integratingthe one or more sensor layers into a band of a wearable device, whereinthe one or more sensor layers form a miniaturized impedance sensor.

In another example, the catalyst layer pattern may include regions ofcatalyst material interspersed with catalyst layer voids between theregions of catalyst material. In another example, the conductive layerpattern may include regions of conductive material interspersed withconductive layer voids between the regions of conductive material. Inanother example, the catalyst layer pattern may be aligned with theconductive layer pattern such that the regions of catalyst layermaterial are stacked on the regions of conductive layer material. Inanother example, cross-linking the interstitial filler may includeexposing the interstitial filler to high-energy light to render theinterstitial filler insolvent. In another example, releasing the sensorsubstrate may include submersing the sensor substrate, the baseinsulating layer, or the sensor layers in a chemical bath and/orplasma-etching the base insulating layer.

In another example, the band may extend at least partially around a bodypart of a user; and the sensor layers are positioned in the band to beadjacent to a section of the body part adjacent to a blood vessel withinthe body part as the user wears the band.

In another example, the nanotube miniaturized electrode may include aforest of carbon nanotubes, wherein the forest of carbon nanotubes mayinclude a bundle of carbon nanotubes aligned approximately parallel toeach other. In another example, the bundle of carbon nanotubes may fillapproximately 0.1 percent to 10 percent of a volume of the forest ofcarbon nanotubes. In another example, the bolstering material mayinclude carbon molecules filling approximately 80 percent to 95 percentof the volume of the forest of carbon nanotubes. In another example, thethin film conductive layer may include nickel, the base insulating layeror the thin film medial insulating layer may include alumina, the sensorsubstrate may include silicon, the thin film catalyst layer may includeiron, the bolstering material may include carbon, and/or theinterstitial filler may include polyimide. In another example,patterning the thin film conductive layer, depositing the thin filmmedial insulating layer, patterning the thin film catalyst layer, and/orgrowing the nanotube miniaturized electrode may include physical vapordeposition or chemical vapor deposition.

In addition or alternative to the blocks show in FIG. 21 , the method2100 may include: patterning a conductive material on a substrate;depositing a medial insulating material on the conductive material;patterning a nanotube growth catalyst material on the medial insulatingmaterial, where a catalyst pattern may be aligned with a conductorpattern formed of the conductive material; growing a miniaturizedelectrode on the nanotube growth catalyst material, where theminiaturized electrode may be aligned with a section of the catalystpattern; applying a hydrophilic treatment, the hydrophilic treatment mayrender the miniaturized electrode hydrophilic; coating the miniaturizedelectrode with an interstitial filler, wherein a top surface of theminiaturized electrode remains exposed from the interstitial filler;cross-linking the interstitial filler to render the interstitial fillersolvent-resistant; and/or scoring or dicing the substrate or the medialinsulating material, where the substrate, the conductive material, themedial insulating material, the nanotube growth catalyst material, theminiaturized electrode, and/or the interstitial filler comprise aminiaturized impedance sensor.

In another example, the method 2100 may include integrating theminiaturized impedance sensor into a wearable device. The integratingmay include attaching the miniaturized impedance sensor to a flexiblecircuit board; and/or overmolding the miniaturized impedance sensor andthe flexible circuit board to form a flexible band, where a top surfaceof the miniaturized electrode may be flush with an inside surface of theflexible band, a top surface of the interstitial filler may be flushwith the inside surface, and/or the miniaturized electrode protrudesfrom the inside surface. In another example, a condition of growing thenanotube miniaturized electrode on the nanotube growth catalyst layerrenders the medial insulating material electrically conductive to allowfor conduction of electricity between the miniaturized electrode and theconductive material. In another example, the scoring or dicing may bebetween a first region of the miniaturized impedance sensor and a secondregion of the miniaturized impedance sensor. The scoring or dicing mayrender the miniaturized sensor flexible. The interstitial filler may beflexible and interconnects the first region and the second region. Thefirst region and the second region may remain locally non-flexible. Inanother example, the scoring or dicing may divide the substrate into afirst miniaturized impedance sensor and/or a second miniaturizedimpedance sensor.

In addition or alternative to the blocks show in FIG. 21 , the method2100 may include: patterning a set of miniaturized electrode pillars ona substrate; and/or coating the set of miniaturized electrode pillarswith an interstitial filler disposed between the set of miniaturizedelectrode pillars. The interstitial filler may insulate the set ofminiaturized electrode pillars from each other; and/or bolster the setof miniaturized electrode pillars. In another example, pattering the setof miniaturized electrode pillars may include forming polymeric pillarsvia photolithography. In another example, the method 2100 may includedepositing a thin film conductive layer on the polymeric pillars and/oretching the thin film conductive layer between the polymeric pillars toelectrically isolate the polymeric pillars from each other. In anotherexample, the set of miniaturized electrode pillars may include bundlesof carbon nanotubes grown in forests on the substrate and infiltratedwith carbon to bolster the carbon nanotubes within the set ofminiaturized electrode pillars. In another example, patterning the setof miniaturized electrode pillars may include printing the miniaturizedelectrode pillars on the substrate. In another example, a resin forprinting the set of miniaturized electrode pillars may include carbonnanotubes mixed into the resin to render the resin conductive.

FIG. 22 illustrates a method 2200 for preparing the miniaturizedimpedance sensor with polymeric nano structures, according to anembodiment. The method 2200 may include patterning one or more polymericpillars onto a device substrate (block 2204). In one embodiment, thepolymeric pillars may be patterned via photolithography using a thicknegative photoresist such as bisphenol-A novolac epoxy (SU-8). Thedevice substrate may include a growth substrate such as the growthsubstrate 402. The device substrate may include a base insulating layersuch as the first insulating layer 404. The device substrate may includepatterned leads, such as the conductive layer 406. The conductive layermay be patterned and/or deposited onto the device substrate in a mannersimilar to that described and/or illustrated regarding block 2004. Thedevice substrate may include polyimide, and/or the conductive layer maybe formed of nickel. The polymeric pillar may be patterned directlyadjacent to the conductive layer on the same surface of the devicesubstrate on which the conductive layer may be formed. For example, thepolymeric pillar may touch the conductive layer. The polymeric pillarmay include a photoresist, according to an embodiment. The photoresistmay, in an embodiment, be a positive photoresist or a negativephotoresist. In an embodiment, the photoresist may include polyimideand/or SU-8.

The method 2200 may include depositing a conductive film on the devicesubstrate, the conductive layer, and/or the polymeric pillar (block2206). In various embodiments, the film may be deposited via sputtering,evaporation, CVD, and so forth. The conductive film may coat thepolymeric pillar and form electrical contact with the conductive layer.The conductive film may be a thin film. The thin film may includecarbon, metal, and/or a polymer-CNT composite, according to anembodiment. In an embodiment, the thin film may include doped zincoxide, tin oxide, and/or indium tin oxide. The thin film may includealuminum-doped zinc oxide, according to an embodiment. A plurality ofpositive regions of the conductive layer and/or corresponding polymericpillars may be formed on the device substrate. In an embodiment, theconductive layer and/or polymeric pillars may be formed according to apattern. Accordingly, the method 2200 may include isolating the thinfilm-coated polymeric pillar and/or the corresponding positive region ofthe conductive layer from neighboring polymeric pillars and/orneighboring positive regions of the conductive layer (block 2208).Isolating the polymeric pillars may include etching, laser-cutting,and/or otherwise cutting through the thin film along a region betweentwo neighboring polymeric pillars and/or positive regions of theconductive layer. In an embodiment, the cutting may include a processthat etches the thin film faster than the device substrate to preventover etch and/or weakening of the device substrate.

The method 2200 may include coating the device substrate, the conductivelayer, the polymeric pillar, and/or the thin film with an interstitialfiller (block 2210). In various embodiments, the coating may be appliedvia spin casting and/or spraying. In an embodiment with a plurality ofneighboring polymeric pillars and/or positive regions of the conductivelayer, the interstitial filler may fill space between the neighboringpolymeric pillars to provide structural support for the pillars. Theinterstitial filler may include SU-8, according to an embodiment. TheSU-8 may be sprayed onto the device substrate to fill the space betweenthe neighboring polymeric pillars and may be etched, such as via UVexposure, to form a trench between the neighboring polymeric pillars andsidewalls at edges of the device substrate. In an embodiment, the photoexposure may be a partial-depth exposure through the device substrate.The interstitial filler may be applied by spraying the interstitialfiller to a height continuous with or above a height of the polymericpillar then allowing a solvent in the interstitial filler to evaporate,according to an embodiment. As the solvent evaporates, the interstitialfiller may shrink to a depth lower than a top portion of the polymericpillar.

FIG. 23 illustrates a method 2300 of 3D-printing a miniaturizedimpedance sensor, according to an embodiment. The method 2300 mayinclude mixing CNTs into a resin (block 2304). The resin may, in anembodiment, include a resin for a rapid prototyping and/or 3D printingmachine. For example, the resin may include a molding resin, anultrasonic embossing resin, a filament, stereolithography resin, and soforth. The CNTs may be obtained via a commercial supplier, and/or may beobtained in a powder form. The resin may be heated to a temperatureabove a melting point of the resin. The CNTs may be removed from thecatalyst layer and mixed into the molten resin. In an embodiment, theresin may be cooled and/or formed into a filament. The filament may bespooled for printing by a 3D printing machine. The method 2300 mayinclude printing the resin onto a device substrate (block 2306). Thedevice substrate may include a growth substrate such as the growthsubstrate 402. The device substrate may include a base insulating layersuch as the first insulating layer 404. The device substrate may includepatterned leads, such as the conductive layer 406. The conductive layermay be patterned and/or deposited onto the device substrate in a mannersimilar to that described and/or illustrated regarding block 2004. Thedevice substrate may include polyimide, and/or the conductive layer maybe formed of nickel. The printed resin may be formed into a pillar and aplurality of pillars may be printed onto the device substrate, accordingto an embodiment. The pillar may form electrical contact with theconductive layer. The method 2300 may include coating the pillar with aninterstitial filler (block 2308). In an embodiment with a plurality ofneighboring pillars, the interstitial filler may fill space between theneighboring pillars to provide structural support for the pillars.

FIG. 24 illustrates a block diagram of electronic components 2400 of awearable device such as the wearable device 100, according to anembodiment. The electronic components 2400 may include a power source2402, a processing device 2404, a sensor interface unit 2406, a dataanalysis unit 2408, a data storage unit 2410, a data communication unit2412, a graphical user interface 2414, and a time reference unit 2416.The electronic components 2400 may be embedded in a band of the wearabledevice and may be electrically coupled to one or more sensors, such asan optical sensor, an impedance sensor, a humidity and/or a temperaturesensor.

In one embodiment, the electronic components 2400 may include a powerunit 2402 that supplies power to components of the electronic components2400. The power unit 2402 may include a battery to supply power and acharging unit that may charge the battery. Alternatively, electroniccomponents 2400 may be connectable to an energy source that powers theelectronic components 2400. In one embodiment, a charger may be used torecharge a battery or other energy source of the power unit 2402. In oneembodiment, an external battery (e.g., located in the band, and soforth) may be coupled to the power unit 2402.

In one embodiment, the electronic components 2400 may include aprocessing device 2404. The processing device 2404 may include a centralprocessor to process the data and/or information of the other componentsthat include the electronic components 2400 or other units, interfaces,and/or devices attached to or in communication with the electroniccomponents 2400.

In another embodiment, the electronic components 2400 may include asensor interface unit 2406. The sensor interface unit 2406 may becoupled to the sensors and/or may perform one or more measurementsrelating to a physiological condition of a body using one or more of thesensors. In one embodiment, the sensor interface 2406 and the processingdevice 2404 may be the same component. In another embodiment, the sensorinterface 2406 may be communicatively coupled to the processing device2404. The sensor interface 2406 may use the one or more sensors to takemeasurements relating to a physiological condition, physiologicalparameter, and/or physiological constituent of a body, an impedancemeasurement, a backscatter measurement, a temperature measurement of abody or of an environment, a humidity measurement of a body or of anenvironment, an airflow measurement (e.g., temperature measurements,pressure measurements, and so forth) of the environment, or anotherphysiological state or environment condition measurement. In anembodiment, the sensor interface 2406 may be coupled to the processingdevice 2404 and the ambient humidity, airflow, skin temperature, and/orambient temperature sensors. In this example, the sensor interface 2406may receive data from the ambient humidity, airflow, skin temperature,and/or ambient temperature sensors relating to the ambient humidity,airflow, skin temperature, and ambient temperature at the location ofthe electronic components 2400. In an embodiment, the sensor interface2406 may be communicatively coupled to the processing device 2404 andthe optical sensor. In this example, the sensor interface unit 2406 mayreceive data from the optical sensor relating to a portion of light thatwas reflected off an artery or other muscular-walled tube.Alternatively, the sensor interface 2406 and the processing device 2404may be the same component. The sensor interface unit 2406 may measurethe backscatter of one or more wavelengths that have been reflected offa vein, artery, or other muscular-walled tube using the portion oflight. In an embodiment, the sensor interface 2406 may becommunicatively coupled to the processing device 2404 and the impedancesensor. In this example, the sensor interface 2406 may receive data fromthe impedance sensor relating to detecting a portion of an electriccurrent. In an embodiment, the sensor interface 2406 may becommunicatively coupled to the processing device 2404, a first humiditysensor, a second humidity sensor, a first temperature sensor, and/or asecond temperature sensor. In this example, the sensor interface 2406may receive data from the humidity and temperature sensors relating tothe humidity and temperature of the user at the location of theelectronic components 2400.

In another embodiment, the electronic components 2400 may include a timereference unit 2416 that generates time reference data usable to controlthe time at which data may be collected from the sensor interface unit2406. The time reference unit 2416 may also be used to calculate spatialand/or temporal derivatives between information received from the sensorinterface unit 2406. In one embodiment, the time reference unit 2416 maykeep track of a calendar time, such as a clock. Alternatively, the timereference unit 2416 may act as a timer, keeping track of a lapsed timeor decrementing from a defined time to zero. The timer of the timereference unit 2416 may be used to collect information or data from thesensor interface 2406 for a defined period of time or to record how longthe sensor interface 2406 collects data.

In another embodiment, the electronic components 2400 may include a dataanalysis unit 2408. The data analysis unit 2408 may be communicativelycoupled to the processing device 2404, sensor interface unit 2406, timereference unit 2416, and other components of the electronic components2400. The data analysis unit 2408 may determine that a physiologicalcondition, physiological parameter, and/or physiological constituent haschanged for a user by comparing temporal data from the time referenceunit 2416 to measurement data from the sensor interface unit 2406. Thedata analysis unit 2408 may communicate the physiological condition,physiological parameter, and/or physiological constituent to a userthrough the graphical user interface (GUI) 2414.

In another embodiment, the electronic components 2400 includes a GUI2414. The graphical user interface may be a monitor screen, liquidcrystal display (LCD), light emitting diode (LED) display, or the like.In one embodiment, the GUI may present information such as a hydrationcondition to the user. In another embodiment, the user may be able tointeract with the electronic components 2400 though inputs or icons onthe GUI.

FIG. 25 illustrates the wearable device 100 in communication 2530 with acomputing device 2520, according to one embodiment. In an embodiment,sensor measurements collected and/or stored by the wearable device 100may be processed or analyzed by a processor or processing device of thewearable device 100 and/or by a computing device 2520 in communicationwith the wearable device 100. The wearable device 100 may be in directand/or indirect communication with the computing device 2520. In oneembodiment, the communication 2530 may be a communication link usingBLUETOOTH® technology, a communication link using ZIGBEE® technology,radio signal, or other direct communication systems. In one embodiment,the other computing device 2520 may be a server that stores information,such as present sensor measurements or sensor measurements previouslytaken by the wearable device 100, or sensor measurements such as bloodglucose measurements taken from a group of individuals, as discussedherein. In another embodiment, the computing device 2520 may be a mobilecomputer device, such as a laptop computer, tablet, or a smartphone. Thewearable device 100 may communicate information, such as sensormeasurements, to the computing device 2520. In an embodiment, thecomputing device 2520 may process and/or analyze the sensor measurementsand/or information received from the wearable device 100. In anotherexample, the computing device 2520 may send processed data, analyzeddata, measurement results, and/or other information to the wearabledevice 100. In another example, the computing device 2520 maycommunicate calibration information to the wearable device 100.

In one embodiment, the wearable device 100 may be a standalone devicewith a processing device to analyze or process: information taken fromone or more sensors 2550 of the wearable device 100; informationreceived from other devices; and/or information stored in a memory ofthe wearable device 100.

In another embodiment, the wearable device 100 may communicate locallywith the computing device 2520 using a wireless communication network ora cellular communication network. The local computing device 2520 may bea smartphone, tablet device, personal computer, laptop, a local server,and so forth. In yet another embodiment, the wearable device 100communicates with a non-local or remote computing device 2520 using thewireless communication network or the cellular communication network.The non-local or remote computing device 2520 may be a remote server, acloud-based server, a back-end server, or other remote electronicdevices.

In an embodiment, the communication 2520 may occur over a wirelesscommunication network. The wireless communication network may be acellular network employing wireless networking standards such as a thirdgeneration partnership project (3GPP®) release 8, 9, 10, 11, 12, 13, 14,or 15 or Institute of Electronics and Electrical Engineers (IEEE®)802.16.2, 802.16k, 802.16.1, 802.16p, 802.16.1b, 802.16n, 802.16.1a, and802.16-2017. In another example, the wearable device 100 may communicatewith the computing device 2520 over a secure wireless local area network(WLAN), a secure personal area network (PAN), and/or a personal widearea network (PWAN). The wearable device 100 in the WLAN may use theWI-FI® technology and IEEE® 802.11 standards defined by the WI-FIALLIANCE® such as the IEEE® 802.11-2016, 802.11ay, 802.11ba, 802.11ax.802.11az, 802.11bb, 802.11bc, 802.11bd, 802.11be, 802.11ah-2016,802.11ai-2016, 802.11aj-2018, 802.11ak-2018, or 802.11aq-2018 standards.Alternatively, the wearable device 100 and the computing device 2520 inthe WLAN may use other technologies and standards. Similarly, thewearable device 100 in the personal area network (PAN) or wirelesspersonal area network (WPAN) may use a BLUETOOTH® technology and IEEE®802.15 standards defined by the BLUETOOTH® Special Interest Group, suchas BLUETOOTH® v1.0, BLUETOOTH® v2.0, BLUETOOTH® v3.0, BLUETOOTH® v4.0,or BLUETOOTH® v5.0 (including BLUETOOTH® low energy). Alternatively, thewearable device 100 in the PAN may use other technologies and standards.In another embodiment, the communications network may be a ZIGBEE®connection developed by the ZIGBEE® Alliance such as IEEE® 802.15.4-2003(ZIGBEE® 2003), IEEE® 802.15.4-2006 (ZIGBEE® 2006), IEEE® 802.15.4-2007(ZIGBEE® Pro). The WLAN or PWAN may be used to transmit data over longdistances and between different local area networks (LANs), WLAN s,metropolitan area networks (MANs), wide area networks (WANs) or otherlocalized computer networking architectures.

The wearable device 100 and the computing device 2520 may be in indirectcommunication using a communications network such as the wirelesscommunication network (such as a network using WI-FI® technology) and/orusing a cellular communication network (e.g., a network using 3rdGeneration Partnership Project (3GPP®), and so forth) to communicatedata or measurement information. In an embodiment, the wearable device100 may take sensor measurements using sensors 2550 and communicate thesensor measurements to the computing device 2520 via the wirelesscommunication network and/or the cellular communication network. Inanother example, the computing device 2520 may receive sensormeasurements from the wearable device 100 via the wireless communicationnetwork and/or the cellular communication network and process the sensormeasurements and/or analyze the sensor measurements. When the computingdevice 2520 has processed the sensor measurements and/or analyzed thesensor measurements, the computing device 2520 may communicate theprocessed sensor measurements, analyzed sensor measurements, sensormeasurement results, or other information to the wearable device 100 viathe wireless communication network and/or the cellular communicationnetwork.

FIG. 26 illustrates a block diagram of the wearable device 100 with acorrelator 2613, a baseliner 2615, and an alerter 2617, according to oneembodiment. The wearable device 100 may include, without limitation, oneor more physiological sensor(s) 2602, one or more Newtonian sensor(s)2604, one or more environmental sensor(s) 2605, one or more locationsensor(s) 2604, a processing device 2603, a memory device 2608, adisplay 2680, a communication interface 2690 (such as a radio frequency(RF) circuit), and an antenna 2692 coupled to the communicationinterface 2690.

In one embodiment, the communication interface 2690 may communicate, viathe antenna 2692, with an external electronic device such as a computingdevice, and with other wireless devices such as electronic device 2600of other users. In an embodiment, the communication interface 2690 maycommunicate the information using a cellular network, a wirelessnetwork, or a combination thereof. In an embodiment, the communicationsnetwork may be the same as or similar to the cellular network describedregarding FIG. 25 . In another example, the wearable device 100 maycommunicate with a device over a secure WLAN, a secure PAN, and/or aPWAN. The wearable device 100 in the WLAN may use technology and/orstandards the same as or similar to those described regarding FIG. 25 .Alternatively, the devices in the WLAN may use other technologies andstandards. Similarly, the wearable device 100 in the PWAN or WLAN mayuse technologies and standards similar to those described regarding FIG.25 . Alternatively, the wearable device 100 in the secure PAN may useother technologies and standards. In another embodiment, thecommunications network may be a ZIGBEE® connection the same as orsimilar to those described regarding FIG. 25 . The WLAN or PWAN may beused to transmit data over long distances and between different LANs,WLANs, MANs, WANs or other localized computer networking architectures.

In one embodiment, the wearable device 100 may communicate data with theother devices via another device, such as a smartphone or tabletcomputing device. For example, the communication interface 2690 may pairwith a smartphone via the wireless network. The smartphone may receivedata using the wireless network and may communicate the data to theother device. In another embodiment, the wearable device 100 maycommunicate information with the other device via repeaters or a relaysystem. For example, a user of the wearable device 100 may be outside acoverage area for the cellular network or the wireless network, e.g., afarm worker out in the field. In this example, the wearable device 100may determine that it is outside the coverage area and switch tocommunicating via the repeaters or the relay system.

In one embodiment, the wearable device 100 may determine it is outside acoverage area when it does not receive a signal from the cellularnetwork or the wireless network. In another embodiment, the wearabledevice 100 may ping the cellular network or the wireless network (suchas a tower within the cellular network or the wireless network) anddetermine that it is outside the coverage area when the wearable device100 does not receive a reply to the ping. In another embodiment,multiple electronic devices 2600 may communicate with each other to forma piconet. In this embodiment, a first electronic device may determineit is outside the coverage area and may scan for a second electronicdevice, where the second electronic device is in the coverage area or incommunication with another electronic device in the coverage area. Whenthe first electronic device finds the second electronic device, thewearable device may communicate information to an end device or to thecellular network or the wireless network via the second electronicdevice.

The processor 2603 may include a first sensor interface 2607 forreceiving sensor data from the physiological sensor(s) 2602, a secondsensor interface 2608 for receiving sensor data from the Newtoniansensor(s) 2604, a third sensor interface 2609 for receiving sensor datafrom the environmental sensor(s) 2605, a fourth sensor interface 2610for receiving sensor data from the location sensor(s) 2606, and aprocessing element 2611. The processing element 2611 in turn may includea correlator 2613, a baseliner 2615 and/or an alerter 2617. The memorydevice 2608 may also include, without limitation, a sensor module 2616,physiological data 2624, environmental data 2626, Newtonian data 2628,and profile data 2630, location data 2632.

The wearable device 100 may include a sensor array with two or moresensors. In the depicted embodiment, the wearable device 100 may includeone or more physiological sensors 2602, one or more Newtonian sensors2604, one or more environmental sensors 2605, one or more locationsensors 2606, or a combination thereof. In some instances, the Newtoniansensors 2604 may be physiological sensors. That is, in some embodiment,the activity level may be determined from one or more physiologicalmeasurements.

A physiological measurement may be any measurement related to a livingbody, such as a human's body or an animal's body. Thy physiologicalmeasurement may correspond to a condition of the body, a parameter ofthe body, or a constituent of the body. A condition of the body mayinclude a heart condition, diabetes, a psychological condition, fatigue,dehydration, and so forth. A parameter of the body may include a bloodpressure, a heart rate, a temperature, pulse oximetry measurement, andso forth. A constituent of the body may include a blood glucose level, aglucose level, an insulin level, a hydration level, a urea content, ahematocrit measurement, and so forth. The physiological measurement maybe a measurement made to assess body functions. Physiologicalmeasurements may be simple, such as the measurement of body or skintemperature, or they may be more complicated, for example measuring howwell the heart is functioning by taking an ECG (electrocardiograph),determining a blood glucose level of the body, or determining ahydration condition of the body. Physiological measurements may alsoinclude motion and/or movement of the body. In some cases, thesephysiological measurements may be taken as an aggregate, e.g., asphysiological data, with which to correlate to other physiologicalmeasurements, a physiological parameter, and/or an environmentalparameter.

A parameter may be considered a measurable quantity (such as heart rate,temperature, altitude, and oxygen level, as just a few examples). Whenmeasurements of parameters are taken in the aggregate, the measurementsmay form data which may be analyzed and correlated to other data orparameters, to identify trends or to identify when meeting (orexceeding) certain thresholds that trigger alerts or other actions andthe like.

The physiological sensors 2602 may include a pulse oximeter sensor, anelectrocardiography (ECG) sensor, a fluid level sensor, an oxygensaturation sensor, a body core temperature sensor, a skin temperaturesensor, a plethysmograph sensor, a respiration sensor, a breath ratesensor, a cardiac sensor (e.g., a blood pressure sensor, a heart ratesensor, a cardiac stress sensor, or the like), an impedance sensor(e.g., a miniaturized impedance sensor), an optical sensor, aspectrographic sensor, an oxygen saturation sensor, humidity and/ortemperature sensors, and/or a microspectrometer. Alternatively, othertypes of sensors may be used to measure physiological measurements,including measurements to determine activity levels of a person wearingthe wearable device.

The Newtonian sensors 2604 may be any of the physiological sensorsdescribed above, but in some cases, the Newtonian sensors 2604 areactivity or motion sensors, such as, for example, a gyroscope sensor, avibration sensor, an accelerometer sensor (e.g., a sensor that measuresacceleration and de-acceleration), a three dimensional (3D)accelerometer sensor (e.g., sensors that measure the acceleration andde-acceleration and the direction of such acceleration andde-acceleration), a force sensor, a pedometer, a strain gauge, amagnetometer, and a geomagnetic field sensor that may be used foractivity level measurements; whereas the physiological sensors 2602 maybe used for specific physiological measurements.

In one embodiment, an environmental measurement may be any measurementof an area approximate or adjacent a user. The environmental sensors2605 may be a humidity sensor, an ambient temperature sensor, analtitude sensor, a barometer, and so forth. A location measurement maybe any measurement of a location of the user or a movement of the user.The location sensor 2606 may be a global positioning system (GPS), atriangulation system, or a location sensor. One or a combination of thephysiological data 2624, the environmental data 2626, the Newtonian data2628, the profile data 2630, and the location data 2632 may be obtainedfrom other sources such as from sources reachable in the cloud oronline, and or through a network such as the networks described and/orillustrated regarding FIG. 25 .

In another embodiment, the environmental measurement may be anymeasurement of a local or central location measurement of where a useris located. For example, one or more environmental sensors 2605 may belocated at a location within a threshold radius of the user, such as athreshold radius from the user location. In this example, theenvironmental sensors 2605 may take environmental measurements and relaythe information to the wearable device 100 or to a communication hubthat has a communication channel established with the wearable device100. Alternatively, the environmental sensors 2605 may takeenvironmental measurements and relay the information to a processing hubthat may analyze the environmental measurements to determine selectedenvironmental factors (such as a humidity level, a heat index, and soforth) and may communicate the environmental factors to the wearabledevice 100 or to another electronic device. In another embodiment, theprocessing hub may receive the environmental measurements from theenvironmental sensors 2605 and other measurements (such as physiologicalmeasurements) from the wearable device 100. The processing hub mayanalyze the environmental measurements and the other measurements todetermine selected result data, such as a hydration level of a user or ahealth level of the user. In another embodiment, the wearable device 100may take a first set of environmental measurements and the localenvironmental sensors 2605 may take a second set of environmentalmeasurements. The first set of environmental measurements and the set ofenvironmental measurements may be combined or aggregated and theprocessing hub and/or the wearable device 100 may analyze the aggregatedenvironmental measurements.

In another embodiment, the environmental measurements may be from anenvironmental information outlet or provider. For example, theenvironmental information outlet or provider may be a weather station, anews station, a television station, an online website, and so forth. Thewearable device 100 or the processing hub may receive the environmentalinformation from the environmental information outlet or provider mayuse the environmental information to determine selected physiologicaland/or environmental data or factors.

The first sensor interface 2607 may be coupled with the one or morephysiological sensors 2602, a second sensor interface 2609 may becoupled with the one or more Newtonian sensors 2604, a third sensorinterface 2609 may be coupled with the one or more environmental sensors2605, and a fourth sensor interface 2610 may be coupled with the one ormore location sensors 2606. The processing element 2611 may be operableto execute one or more instructions stored in the memory device 2608,which may be coupled with the processor 2603. In some cases, theprocessing element 2611 and memory device 2608 may be located on acommon substrate or on a same integrated circuit die. Alternatively, thecomponents described herein may be integrated in one or more integratedcircuits. The memory device 2608 may be any type of memory device,including non-volatile memory, volatile memory, or the like. Althoughnot separately illustrated the memory device may be one or more types ofmemory configured in various types of memory hierarchies.

The memory device 2608 may store physiological data 2624, such ascurrent and past physiological measurements, as well as profile data2630, including user profile data, bibliographic data, demographic data,and the like. The physiological data 2624, and in some cases the profiledata 2630, may also include processed data regarding the measurements,such as statistical information regarding the measurements, as well asdata derived from the measurements, such as predictive indicators,results, and/or recommendations.

In an embodiment, the profile data 2630 may also include informationconnected to user profiles of the users that wear the wearable device100, such as a gender of the user, an age of the user, a body weight ormass of the user, a health status of the user, a fitness level of theuser, or a family health history of the user. In another example, theprofile data 2630 may include occupational information of the users thatwear the wearable device 100, such as a job type, a job title, whetherthe job is performed indoors or outdoors, a danger level of the job, andso forth. For example, the job types may include an elderly live-at-homejob, an oil driller, a construction worker, a railroad worker, a coalmine worker, a job in confined spaces, a fireman, a construction worker,an outdoor worker, an office worker, a truck driver, a child, astay-at-home parent, a disabled individual, or any other occupationwhich might provide an individual with income and/or otherwise occupythe individual's time.

In an embodiment, the wearable device 100 may receive the profile data2630 via a touch screen device integrated into the wearable device 100or coupled to the wearable device 100. In another example, the wearabledevice 100 may receive the profile data 2630 via a communication port ofthe wearable device 100. For example, the wearable device 100 mayreceive profile data 2630 from another device via a wired communicationconnection (e.g., a universal serial bus) or via a wirelesscommunication connection (e.g., a BLUETOOTH® communication technology).

The profile data 2630 may also be linked to various physiological data2624 and Newtonian data 2628 and be tracked over time for the users. Theprofile data 2630 may also include baselines of physiological parametersfor respective users. In an embodiment, the baselines are of a heartrate, a blood pressure, bioimpedance, skin temperature, oxygen levels,hydration levels, electrolyte levels, blood glucose levels, and soforth. When the baselines are included with the user profiles, the userprofiles may be referred to as baseline profiles for the respectiveusers.

The memory device 2608 may also store the environmental data 2626, theNewtonian data 2628, the profile data 2630, and/or the location data2632. The Newtonian data 2628, environmental data 2626, or location data2632 may be current and past measurements, as well predictive data forpredictive modeling of activity levels, environmental levels, orlocations. The memory device 2608 may store instructions of the sensormodule 2616 and instructions and data related to the correlator 2613,the base liner 2615 and the alerter 2617, which perform variousoperations described below.

In particular, the sensor module 2616 may perform operations to controlthe physiological sensors 2602, Newtonian sensors 2604, environmentalsensors 2605, and location sensors 2606, such as when to tum them on andoff, when to take a measurement, how many measurements to take, howoften to perform measurements, and so forth. For example, the sensormodule 2616 may be programmed to measure a set of physiologicalmeasurements according to a default pattern or other adaptive patternsto adjust when and how often to take certain types of measurements. Themeasurements may be stored as the physiological data 2624, theenvironment data 2626, and the Newtonian data 2628, location data 2632,and some of them may also be integrated as a part of the profile data2630, as discussed.

In an embodiment, the processing element 2611 (e.g., one or moreprocessor cores, a digital signal processor, or the like) may executethe instructions of the sensor module 2616 and those related to thecorrelator 2613, the baseliner 2615, the alerter 2617 and/or othermodules or routines. Alternatively, the operations of the sensor module2616 and the correlator 2613, the baseliner 2615, and the alerter 2617may be integrated into an operating system that may be executed by theprocessor 2603. In one embodiment, the processing element 2611 measuresa physiological measurement via the first sensor interface 2607. Theprocessing element 2611 may measure an amount of activity of thewearable device 100 via the second sensor interface 2608. The amount ofactivity could be movement or motion of the wearable device 100 (e.g.,by tracking location), as well as other measurements indicative of theactivity level of a user, such as heart rate, body temperature, skinluminosity, or the like. The processing element 2611 may measure anenvironmental measurement via the third sensor interface 2609. Theprocessing element 2611 may measure a location measurement via thefourth sensor interface 2610.

In one embodiment, the Newtonian sensors 2604 may include a hardwaremotion sensor to measure at least one of movement or motion of thewearable device 100. The processing element 2611 may determine theamount of activity based the movement or motion of the wearable device100. The hardware motion sensor may be an accelerometer sensor, agyroscope sensor, a magnetometer, a GPS sensor, a location sensor, avibration sensor, a 3D accelerometer sensor, a force sensor, apedometer, a strain gauge, a magnetometer, and a geomagnetic fieldsensor.

The processor 2603 may further execute instructions to facilitateoperations of the wearable device 100 that receive, store and analyzemeasurement data, environmental data, location data, and profile data.The indicator(s) 2618 may include one or more of a light, a display, aspeaker, a vibrator, and a touch display, useable to alert the user totake actions in response to trending levels of: physiological parametersduring or after physical activity and/or prepare for undertakinganticipated physical activity; environmental parameters; activityparameters, or location parameters.

In some embodiments, for example, the correlator 2613 may analyzemeasurement data to correlate physiological data, environmental data,activity data, location data, or user experienced feedback with aphysiological parameter, environmental parameter, activity parameter, alocation parameter, or user experienced feedback to predict a change ina level of the physiological parameter, environmental parameter,activity parameter, or a location parameter. In one embodiment, the userexperienced feedback may be physiological or psychological symptomsexperienced by the user. For example, the physiological or psychologicalsymptoms may include: headaches, dizziness, tiredness, mental fatigue,increased thirst, dry mouth, swollen tongue, physical weakness,confusion, sluggishness, and so forth.

Such prediction may enable timely and accurate recommendations to a userin terms of blood glucose levels (e.g. consuming food or taking aninsulin shot, and so forth), adjusting effort levels or other specificactions to address a trend or a change in the physiological parameter,the environmental parameter, the activity parameter, or the locationparameter. The recommendations may be displayed in the display 2680,sent via an alert through one of the indictor(s) 2618 or displayed inanother device such as a smart phone or tablet or other computingdevice.

In another embodiment, the correlator 2613 may also track and analyzeNewtonian data of the user related to physiological or determinedparameters (such as heart rate, oxygenation, skin luminosity, hydration,and the like), related to location and type of activity (such asactivity levels associated with being at the gym, riding a bike,attending class, working at a desk, sleeping, or driving in traffic, andthe like) and/or related to scheduling information (such as appointmentson a calendar, invites received from friends, or messages related totravel and/or activity plans, and the like). Through this analysis, thewearable device 100 may track activity data over time, intelligently andcontinuously (or periodically) analyze all of this information and alertthe user through the indicator(s) 2618 to take a specific action at aproper time before a start of a dehydration condition. The specificaction may include to hydrate extra for a time period before physicalactivity and to eat at least two hours before any physical activity, orother such timing that may be general to most users or customized to atraining or nutrition routine of a specific user.

In another embodiment, the correlator 2613 may build an individualizedprofile for the user. The correlator 2613 may receive the individualizedprofile information from an input device of the wearable device 100. Forexample, the correlator 2613 may receive the individualized profileinformation from a touch screen of the wearable device 100. In anotherexample, the correlator 2613 may receive the individualized profileinformation from a device in communication with the wearable device 100(such as via a USB port or using a BLUETOOTH® technology). In anotherembodiment, the wearable device 100 may include a memory that stores theindividualized profile information for the user.

In another embodiment, the correlator 2613 may utilize data frommultiple physiological sensors 2602 integrated into the wearable device100 to determine a physiological condition of the user. For example, thewearable device 100 may be configured to measure blood glucose. Bloodglucose may be determined by illuminating a vein and/or artery andprocessing light reflected off the vein and/or artery. By processing thereflected light and comparing the reflected wavelengths to wavelengthsknown to be reflected by various blood and/or body constituents, apercentage of the blood constituting blood glucose may be determined. Aperson may be determined to be hyperglycemic or hypoglycemic based onthe percentage of blood glucose. However, the blood glucose percentagemay be affected by the percentage of other blood constituents. A primaryconstituent of blood is water. Thus, if the user is dehydrated, thepercentage of blood glucose may be higher for the user than when theuser is properly hydrated, and it may incorrectly be determined the useris hyperglycemic.

In an embodiment, the correlator 2613 may use a measurement taken by onephysiological sensor 2602 to calibrate a measurement taken by anotherphysiological sensor 2602 and thereby prevent false positives for thephysiological condition. For example, the user may want to know theblood glucose level. The wearable device 100 may include a light sourceand microspectrometer, and a miniaturized impedance sensor. Theprocessor 2603 may obtain a blood glucose measurement by the lightsource and microspectrometer, and may obtain a hydration level by theminiaturized impedance sensor. The blood glucose and hydration data maybe received by the correlator 2613. The correlator 2613 may determine,based on the hydration condition, an expected percentage of water inblood of a user. For example, the memory device 2608 may have stored inthe physiological data 2624 a table relating various impedancemeasurements to various hydration levels, which hydration levels may berelated to a volume of water in the measured tissue and/or tissues. Inturn, the hydration levels may be related to various percentages ofwater in blood. The correlator 2613 may compare the percentage of waterin blood obtained from the impedance measurement to the percentage ofglucose in the blood determined by the spectroscopy measurement. In aspecific example, the correlator 2613 may determine the user haselevated blood glucose percentage, but the elevation is due todehydration.

In an embodiment, the miniaturized impedance sensor may take consecutiveimpedance measurements at a discreet frequency. In another embodiment,the miniaturized impedance sensor may take consecutive impedancemeasurements at different frequencies, thereby functioning as animpedance spectrometer. For example, the miniaturized impedance sensormay take a first measurement at 5 kilohertz, a second measurement at 50kilohertz, a third measurement at 500 kilohertz, a fourth measurement at5 megahertz, a fifth measurement at 50 megahertz, and a sixthmeasurement at 500 megahertz. In general, a range of frequencies used tointerrogate the body part of the user may range from 5 kilohertz to 500kilohertz. In one embodiment, the discreet frequency may include 200kilohertz and/or 200 megahertz. A frequency and/or range of frequenciesmay correspond to absorption harmonics of constituents of the body part,such as molecules that make up the body part, structures within the bodypart, fluids within the body part, and so forth.

The individualized profile may include physiological informationassociated with the user. For example, the physiological information mayinclude a healthy blood glucose range for the user, an average heartrate of the user, an age of the user, a health level of the user, and soforth. The individualized profile may also include informationassociated with a location or environment that the user may be located.For example, the individualized profile may include: humidity levelinformation, such as when the user is located in a dry climate or in ahumid climate; altitude level information, such as when the user islocated at a relatively high altitude or a relatively low altitude;seasonal information, such as if it is winter where the user may belocated or summer. The correlator 2613 may also determine anenvironmental effect on the user for the location where the user may belocated at. For example, if the user is located at their home that is ata high altitude with a dry climate and it is a winter season, thecorrelator 2613 may determine that the user may be acclimated to highaltitudes, dry climates, and the winter season. The correlator 2613 mayalso update the user profile when the user changes location. Forexample, when the user leaves their home location and goes on a vacationto a location that is at a low altitude, a humid climate, and it is asummer season, the correlator 2613 may determine that the user may notbe acclimated to the low altitude, humid climate, and summer season.

In one embodiment, the wearable device 100 may alert the user of thechanges to the individualized profile. In another embodiment, thewearable device 100 may alert the user of to effects associated with thechanges to the individualized profile. For example, the wearable device100 may access a table of predetermined effects of the user changingtheir user profile. In an embodiment, the table may indicate that whenthe user switches from a low altitude to a high-altitude location, theuser may experience altitude sickness. In another example, the table mayindicate that when the user switches from a dry climate to a humidclimate location, an ability of a body of the user to cool itself downmay be decreased when an ambient temperature is relatively high. Inanother embodiment, the table may indicate when the current user profileindicates safety risks or physiological performance changes.

In another embodiment, the individualized profile may also includeinformation associated with clothing or apparel worn by the user of thewearable device 100. For example, the individualized profile mayindicate that a user may wear different types of apparel for differentenvironments including: a thickness of fabric; a type of a fabric, suchas wool or cotton; a number of clothes layers worn by the client;accessories worn by the client, such as hard hats, steel-toed shoes,safety googles, safety belts, and so forth; and gender types of apparel,such as women's and/or men's apparel. In an embodiment, the correlatormay adjust measurement information or measurement results based on thedifferent types of clothing or apparel. For example, the correlator 2613may determine that the user is a firefighter and is wearing multiplelayers of clothing to protect against fire. In this example, thecorrelator 2613 may determine that a cause of a hydration level of theuser decreasing may be the multiple layers of clothing cause thefirefighter to sweat more and lose more fluid than a typical number oflayers of clothing worn by the user. In another example, the correlator2613 may determine that the user is a marathon runner who is running. Inthis example, the correlator 2613 may determine that a cause of a bloodglucose level of the user decreasing may be the extended period ofrunning using all freely available blood glucose.

In one embodiment, the alerter 2617 may decide the most appropriatetiming and mode of alert, whether through one of the indicator(s) 2618,the display 2680 or another device such as a smart phone, tablet or thelike. The type of indicator used to alert the user may also becustomized to or by the user. For example, the alerter 2617 maydetermine blood glucose of a user is in a moderately high range suchthat the user should take an insulin shot and/or may alert the user totake an insulin shot.

In one embodiment, the correlator 2613 may determine a correlationbetween different data points or data sets of the input data (such asdata collected from different sensors, devices, or obtained from thecloud or online). The correlator 2613 may determine different types ofcorrelations of the data points or data sets. In an embodiment, thecorrelator 2613 may execute a Pearson product moment correlationcoefficient algorithm to measure the extent to which two variables ofinput data may be related. In another example, the correlator 2613 maydetermine relations between variables of input data based on asimilarity of rankings of different data points. In another example, thecorrelator 2613 may use a multiple regression algorithm to determine acorrelation between a data set or a data point that may be defined as adependent variable and one or more other data sets or other data pointsdefined as independent variables. In another example, the correlator2613 may determine a correlation between different categories orinformation types in the input data.

In further examples, when the correlator 2613 determines a correlationbetween the different data points or data sets, the correlator 2613 mayuse the correlation information to predict when a first event orcondition may occur based on a second event or condition occurring. Inanother example, when the correlator 2613 determines a correlationbetween the different data points or data sets, the correlator 2613 mayuse the correlation information to determine a blood glucose level. Asdiscussed in the preceding paragraphs, a high blood glucose level may bean event that negatively impacts safety or health of the user. Inanother example, when the correlator 2613 determines a correlationbetween the different data points or data sets, the correlator 2613 mayuse the correlation information to determine a cause of a conditionand/or event, such as a hydration condition.

Additionally, or alternatively, the correlator 2613 may determine acorrelation between physiological data 2624, environmental data 2626,Newtonian data 2628, profile data 2630, and location data 2632. Forexample, the input data may include blood glucose level data(physiological data) and ambient temperature data (environmental data).In this example, the correlator 2613 may identify a correlation betweenan ambient temperature, an amount of sweating, a blood glucose level ofa user, and a hyperosmolar hyperglycemic state (HHS). The correlator2613 may identify the correlation between the ambient temperature, theamount of sweating, the blood glucose level, and the HHS by using aregression algorithm with the HHS as an independent variable and theambient temperature, the amount of sweating, and the blood glucose levelas dependent variables. When the correlator 2613 has identified thecorrelation between the HHS, the ambient temperature, the amount ofsweating, and the blood glucose level, the correlator 2613 may predictaltered consciousness, confusion, disorientation, and/or a coma based ona change in a the blood glucose level of a user or a rate of change of ablood glucose level of a user, a change in the amount of sweating of theuser or a rate of change in the amount of sweating of the user, and achange in the ambient temperature or a rate of change in the ambienttemperature.

Additionally, or alternatively, the correlator 2613 may determine acorrelation between a fatigue event, an altitude level, and anoxygenation level of a user. For example, the correlator 2613 maydetermine a correlation between an increase in the altitude level, adecrease in the oxygenation level of the user, and an increase in afatigue event. When the correlator 2613 determines the correlationbetween the altitude level, the oxygenation level, and the fatigueevent, the correlator 2613 may predict an increase or decrease in aprobability of a hydration condition change based on a change in theoxygenation level of user and the altitude level at which the user maybe currently at. In an embodiment, the correlator 2613 may use theindividualized profile information (as discussed in the precedingparagraphs) of the user to determine the predicted increase or decreasein the probability of a hydration condition change. For example, thecorrelator 2613 may determine a change in altitude level of the userfrom a relatively low altitude to a relatively high altitude. Thecorrelator 2613 may use the individualized profile information todetermine that the user may be acclimated to the relatively highaltitude (such as if they live at a high altitude) and adjust thepredicted increase or decrease in the probability of a hydrationcondition change for the change in altitude in view of theindividualized profile information. For example, the correlator 2613 maypredict that the change from the low altitude to the high altitude willnot increase or decrease the probability of a user experiencing adangerous change in hydration condition.

In a further example, the correlator 2613 may identify a correlationbetween location information and physiological data of a user. Forexample, the correlator 2613 may determine a location of a user for at aperiod of time, such as by using GPS sensor data or triangulation sensordata. In this example, the correlator 2613 may receive physiologicalmeasurement data (such as heart rate measurement data, opticalspectroscopy data, blood glucose level measurement data, blood pressuremeasurement data, hydration condition data, and so forth). Thecorrelator 2613 may correlate the location of the user with thephysiological measurement data to increase an accuracy of data analysis,a diagnosis, or result data and/or provide additional details regardinga cause of a change in a blood glucose level.

In an embodiment, the correlator 2613 may determine that a user may beat work in an office location. When the correlator 2613 detects anincrease in a heart rate or a blood pressure of a user, the correlator2613 may correlate heart rate or blood pressure data and the locationinformation to determine a cause of the cognitive ability reductionevent. For example, when a heart rate or blood pressure of a userincreases while at a work in an office, the correlator 2613 maydetermine that the heart rate or blood pressure increase may be due topsychological causes (such as stress) rather than physiological causes(such as exercising or working out) because the user may be at alocation where the user may not be likely to physically exert himself orherself.

In another example, the correlator 2613 may determine an occupation ofthe user, such as by using the profile data 2630. In one embodiment, thecorrelator 2613 may determine that the occupation of the user may be ahigher risk occupation (e.g., a statistically more dangerousoccupation). For example, the correlator 2613 may access a database orlist (stored at the memory device 2608 or externally) that includesinformation associated with an occupation, such as environmentalexposure. When the correlator 2613 detects that the occupation of theuser may be a higher risk occupation (e.g., an occupation with a risklevel that exceeds a threshold value), the correlator 2613 may correlatedata such as heart rate data, blood pressure data, hydration level data,with the occupational information to determine a cause of a hydrationcondition change. For example, when a heart rate and blood pressure of auser increases and a hydration level of the individual decreases whilethe individual is working at an oil refinery or on a farm, thecorrelator 2613 may determine that the heart rate or blood pressureincrease may be due to physiological influences of the occupation (suchas strenuous labor or no breaks) rather than psychological causes (suchas stress) because the occupation where the individual is working at maybe likely to include physical exertion.

In a further example, the correlator 2613 may use a multiple regressionalgorithm to determine a correlation between multiple data points ordata sets and a physiological condition. For example, the correlator2613 may receive heart rate data, skin temperature, bioimpedance data,skin luminosity, and hydration level data of a user. In this example,the correlator 2613 may determine a correlation between these types ofphysiological data and a physiological condition change event of theindividual. For example, the physiological data could be from opticalspectroscopy (skin luminosity) and/or bioimpedance data. The correlator2613 may then determine that as the bioimpedance of a user increases andskin luminosity increases, a probability of a dehydration eventoccurring increases.

Additionally, or alternatively, the correlator 2613 may filter out acorrelation determination (e.g., a determination that data points ordata sets and a blood sugar condition may be correlated) when acorrelation level is below a threshold level. For example, when thecorrelator 2613 determines that there may be a 30 percent correlationbetween a skin temperature or a bioimpedance level of a user and a fallevent, the correlator 2613 may filter out or disregard the correlationinformation when determining a cause of the fall event. In anotherexample, the correlator 2613 may use a learning algorithm or machinelearning to determine when to filter out a correlation determination.For example, at a first instance of a fall, there may be a 30 percentcorrelation between a skin temperature or a bioimpedance level of a userand a fall event. The correlator 2613 may monitor multiple fall eventsand use machine learning to determine that the initial 30 percentcorrelation is actually a 60 percent correlation and adjust the filterto not filter out the correlation between the skin temperature or thebioimpedance level of a user and a fall event or assign the correlationof the skin temperature or the bioimpedance level of a user and a fallevent a different weight.

Additionally, or alternatively, the correlator 2613 may filter out thecorrelation determination based on a schedule of a user. For example,when the correlator 2613 determines that a user may be taking a lunchbreak, off of work, or sleeping, the correlator 2613 may filter outenvironmental conditions that are associated with the occupation of theuser, e.g., the correlator 2613 may filter out false positives.

Additionally, or alternatively, the correlator 2613 may discount orweight a correlation determination based on the correlation level of thecorrelation determination. For example, when the correlator 2613determines that there may only be a 30 percent correlation between anoccupation of a user and a blood glucose level of a user, the correlator2613 may discount or assign a lower weight to the correlationdetermination (relative to a higher correlation percentage such as 90percent) when determining a change in blood sugar condition.

Additionally, or alternatively, the correlator 2613 may assign weightsto different factors, such as: physiological data 2624 (e.g., differenttypes or qualities of physiological parameters), environmental data 2626(e.g., different types or quality of environmental parameters),Newtonian data 2628 (e.g., different types or quality of Newtonianparameters), profile data 2630, location data 2632 (e.g., differenttypes or quality of location parameters), a time of day, and so forth.In an embodiment, the correlator 2613 may assign a first weight to bloodglucose level data of a user and a second weight to profile data of auser when determining a probability of a change in blood sugar conditionfor a user. In this example, when determining the probability of achange in a blood sugar condition, the correlator 2613 may assign ahigher weight to the blood glucose level data relative to the profiledata, for example.

The correlator 2613 may additionally, or alternatively, usepredetermined weights for the physiological data 2624, environmentaldata 2626, Newtonian data 2628, profile data 2630, and location data2632. In another example, the correlator 2613 may receive user definedor predefined weights from an input device indicating the weights forthe different physiological and/or environmental data. In anotherexample, the correlator 2613 may determine the weights to assign to thephysiological data 2624, environmental data 2626, Newtonian data 2628,profile data 2630, and location data 2632 based on correlation levels ofthe physiological data 2624, environmental data 2626, Newtonian data2628, profile data 2630, and location data 2632. For example, when acorrelation level between a hydration condition and a heart rate of auser may be relatively low over a threshold period of time and/or undera threshold number of different conditions, the correlator 2613 mayassign a low weight to heart rate data when determining a cause of achange in hydration condition.

In an embodiment, the correlator 2613 may assign different weights toone or more of the physiological data 2624, environmental data 2626,Newtonian data 2628, profile data 2630, and location data 2632 based onother physiological data 2624, environmental data 2626, Newtonian data2628, profile data 2630, and location data 2632. For example, based on alocation of a user, the correlator 2613 may assign a first weight toenvironmental data 2626 and a second weight to profile data 2630. Inanother example, the correlator 2613 may assign weights to differenthydration and/or blood sugar conditions.

Additionally, or alternatively, the correlator 2613 may useenvironmental data 2626 or location data 2632 to determine a cause of achange in hydration condition. For example, when a user may be locatedat a fitness facility working out, the correlator 2613 may increase aweight for a physical exertion related a change in a hydration conditionoccurring because of in physical exertion of a user (such as an increasein a heart rate or decrease in a hydration level of a user). In anotherexample, when a user may be located at home in bed resting or sleeping,the correlator 2613 may correlate a location of the user with thehydration condition of the user. In this example, the correlator 2613may determine that a decrease in probability of a change in a hydrationcondition occurring due to a user being located in their bedroom for athreshold period of time (e.g., a safer environment).

In one embodiment, the correlator 2613 may determine a weighting ofmeasurement information or physiological information using medicalevaluation information. In an embodiment, the medical evaluationinformation includes medical evaluation information of the user, such asa medical physical. The medical evaluation information may include:medical history and health history information, such as whether the usermay be a smoker or a non-smoker; blood pressure information of the user;hereditary diseases information of the user; sexual health informationof a user; dietary information of a user; exercise routine informationof the user, such as how often the user exercises; heart or lungexamination information of the user; blood sugar test results of theuser; and so forth. In an embodiment, the correlator 2613 may use themedical evaluation information to set initial weight for different datatypes. The correlator may update or adjust the weights for the differentdata types using machine learning. For example, the physiological data2624, environmental data 2626, and Newtonian data 2628 may be assigned afirst set of weights based on the medical evaluation information. As thewearable device 100 uses the sensors to collect the physiological data2624, environmental data 2626, and the Newtonian data 2628, thecorrelator 2613 may use the physiological data 2624, the environmentaldata 2626, and the Newtonian data 2628 to customize the weighting of themeasurement information or physiological information to the individual.For example, the correlator 2613 may receive medical evaluationinformation for the user input device of the wearable device 100 usingan input device of the wearable device 100.

The correlator 2613 may track, sort and/or filter input data. The inputdata may include: user schedule information, such as a daily schedule ofthe user; survey information, such as information received from surveysof individuals; research information, such as clinical researchinformation or academic research information associated with one or moreblood sugar conditions of the wearable device; and so forth.

The correlator 2613 may use location-based tracking and/or schedulinginformation of the user in determining an expected or probable change ina blood sugar condition. For example, the correlator 2613 may receivelocation data indicating the user may be at a restaurant, or thecorrelator 2613 may receive schedule data of the user indicating theuser may be scheduled for a lunch meeting. In this example, thecorrelator 2613 may use the location and/or schedule information toanticipate that the user may be eating and increase a probability that achange a in diabetic condition may occur.

The correlator 2613 may use timer information determining an expected orprobable occurrence of a change in a blood sugar condition. For example,the correlator may monitor how long it may have been since a user had aninsulin shot. In this example, as the length of time increases since thelast insulin shot, the probability that a change in blood sugarcondition may occur increases. In another example, the correlator 2613may use the timer information to periodically request a response fromthe user. For example, when a timer has expired for a maximum amount oftime between insulin shots, the correlator 2613 may request a responsefrom the user as to whether the user has taken an insulin shot.

In another example, the correlator 2613 may have a work mode (the useris at work) and a home mode (the user is at home), where a type ofenvironmental condition that the wearable device monitors for and/or aprobability of a change in a blood sugar condition occurring mayincrease or decrease when switching between the work mode and the homemode. For example, when the user has a high-activity-level occupation,the correlator 2613 may monitor for change in a hydration conditionand/or blood sugar condition related to the occupation when thecorrelator may be in a work mode and switch to monitoring for changes ina hydration condition and/or blood sugar condition related tolow-exertion activities when the correlator may be in a home mode.

In another example, the correlator 2613 may use the schedulinginformation in correlation with a location of the user to determine anexpected or probable change in a hydration condition and/or blood sugarcondition. For example, the scheduling information may indicate that theuser may be scheduled to attend an awards banquet and dinner at aconference center and the correlator 2613 may adjust the types orprobabilities of a change in a blood sugar condition occurring in viewof the scheduling information. In this example, while the correlator2613 may typically decrease a probability of a change in blood sugarcondition occurring for the user based on the location information(e.g., the conference center), the correlator 2613 may adjust the typesor probabilities of a change in a blood sugar condition occurring inview of the scheduling information that the user may be eating at theawards banquet.

Additionally, or alternatively, the correlator 2613 may track and updateactivity levels of users and correlate these levels with blood sugarconditions over time. For example, the GPS sensor of the wearable device100 may indicate that the user usually goes to a restaurant around 12:00pm on weekdays, and usually goes to a restaurant around 7:00 pm onSaturdays. Although these activities may not be available within thescheduling information or data of the wearable device 100 (or othertethered device), the correlator 2613 may execute machine learning toadd to activity data of the user these events that normally occur.

The wearable device 100 may store historical or previous blood sugarcondition information of the user. In an embodiment, the correlator 2613may store the historical information on the memory device 2608 of thewearable device 100. In another example, the correlator 2613 may use acommunication device and/or the communication interface 2690 to storethe blood sugar condition information on a memory device coupled to orin communication with the wearable device, such as a cloud-based storagedevice or a memory device of another computing device. In anotherexample, the correlator 2613 may be part of a cloud-based system or theother computing device.

The correlator 2613 may filter and/or sort hydration condition and/orblood sugar condition information. In an embodiment, the correlator 2613may receive a filter or sort command from the wearable device or aninput device to filter and/or sort the hydration condition and/or bloodsugar information. In another example, the filter or sort command mayinclude filter parameters and/or sort parameters.

In another example, the correlator 2613 may sort and/or filter the inputdata based on a trending of blood sugar conditions. For example, thecorrelator 2613 may sort blood sugar conditions that may be trending inan increasing direction or a decreasing direction and may sort the bloodsugar conditions based on the trending. In this example, different bloodsugar conditions for a user may be trending in different directions,such as a diabetic event of a user may be increasing in trending andeating events may be stable or stagnant.

In another embodiment, the baseliner 2615 may receive profileinformation from a new user to include any or a combination of gender,age, weight, health, fitness level, and family health histories. Thehealth and fitness levels of the user may be based at least in part onphysiological measurements received from the physiological sensor(s)2602 and the activity data received from the Newtonian sensors 2604. Thebaseliner 2615 may then identify, from one or more baseline profiles ofother users (e.g., a group of users), a baseline profile that may bemost similar to the user profile based on a correlation between the userprofile information and baseline profile information. The baselineprofiles may include baseline information of a probability of a changein blood sugar conditions occurring for a user. The user profiles mayinclude information of the types of blood sugar conditions that may beprobable to occur for a user in the group of users.

The baseliner 2615 may then be able to set a baseline against which tojudge a blood sugar condition. In an alternate embodiment, the baselineprofile that may be most similar to the user profile is identified froman aggregated baseline profile for one or more individuals correspondingto the one or more baseline profiles. Alternatively, or additionally,the most similar profiles may look at a blood sugar condition thatoccurs for the individual as compared to individuals in the group. Forexample, the user may be most similar to another individual because theyboth react physiologically similarly to periods of fasting. In anotherexample, the user may have a similar blood sugar profile to themost-similar profile, meaning, when the user fasts the user may reach ablood glucose level at a certain point in time that substantiallymatches the timing of the most-similar profile.

The wearable device 100 may further receive survey information and/orresearch information from an input device with which to build or add tothe user and/or baseline profiles. For example, the wearable device 100may receive survey information that includes: gender information, ageinformation, physical weight information, general health information,family information, fitness level information, and so forth. In anembodiment, the correlator 2613 may determine a correlation between thesurvey information and user input data. For example, the correlator 2613may correlate the age, weight, fitness level, and general health levelof a user with survey information from other individuals to determine acorrelation between the survey information for the individual and theother individuals. In this example, the baseliner 2615 may set abaseline for a measurement of the wearable device 100 for the individualbased on baselines for the other individuals with the same or similarsurvey information.

In another example, the correlator 2613 may correlate the userinformation with research information (such as research papers, clinicalstudies, and so forth). For example, the wearable device may retrieveresearch information related to a physiological parameter, thecorrelator 2613 may correlate the research information with hydrationconditions and/or blood sugar conditions for the user to generate aresearch correlation. The baseliner 2615 may then adjust the baselineset for the user related to the hydration conditions and/or blood sugarconditions in response to the research correlation.

The correlator 2613 may store physiological condition information in aphysiological condition database 2612. In one embodiment, the correlator2613 may determine parameters associated with physiological conditions.The parameters may include threshold values for measurements or datavalues, such as physiological sensor measurements, environmental sensormeasurements, Newtonian sensor measurements, location sensormeasurements, or profile data 2630. The correlator 2613 may store thephysiological condition and the associated blood sugar parameters in thephysiological condition database 2612. In an example, the correlator2613 may determine these parameters may store the physiologicalcondition with the associated parameters in the physiological conditiondatabase 2612. In another example, the physiological condition database2612 may store predetermined physiological conditions with theassociated parameters. In another example, the physiological conditiondatabase 2612 may receive the physiological conditions and theassociated parameters from another device or server 2694.

The preceding examples are intended for purposes of illustration and arenot intended to be limiting. The correlator 2613 may identify acorrelation between various data points, data sets, data types, and/orphysiological conditions such as hydration conditions and/or blood sugarconditions. After having a correlation that informs, for example, adiabetic event, the blood glucose level, a dehydration event, thehydration condition and/or other related physiological condition of theuser, and further in consideration of a present activity of the user,the alerter 2617 may alert the user at the proper time how to moderateactivities such as eating or exercising to avoid or minimize a diabeticevent and/or dehydration event.

As used herein, one or more items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary. In addition, various embodiments and examples of the presentdisclosure may be referred to herein along with alternatives for thevarious components thereof. It may be understood that such embodiments,examples, and alternatives are not to be construed as defactoequivalents of one another but are to be considered as separate andautonomous representations of the present disclosure.

Furthermore, the described features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments. In theforegoing description, numerous specific details are provided, such asexamples of layouts, distances, network examples, and so forth, toprovide a thorough understanding of embodiments of the disclosure. Oneskilled in the art will recognize, however, that the disclosure may bepracticed without one or more of the specific details, or with othermethods, components, layouts, and so forth. In other instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring embodiments of the disclosure.

While the foregoing examples are illustrative of the principles of thepresent disclosure in one or more particular applications, numerousmodifications in form, usage and details of implementation may be madewithout the exercise of inventive faculty, and without departing fromthe principles and concepts of this disclosure. Accordingly, it is notintended that this disclosure be limited, except as by the claims.

The words “example” or “embodiment” are used herein to mean serving asan example, instance or illustration. Use of the words “example” or“embodiment” may be intended to present concepts in a concrete fashion.As used in this application, the term “or” may be intended to mean aninclusive “or” rather than an exclusive “or.” That is, unless specifiedotherwise, or clear from context, “X includes A or B” may be intended tomean any of the natural inclusive permutations. That is, if X includesA; X includes B; or X includes both A and B, then “X includes A or B”may be satisfied under any of the foregoing instances. In addition, thearticles “a” and “an” as used in this application and the appendedclaims should generally be construed to mean “one or more” unlessspecified otherwise or clear from context to be directed to a singularform. Moreover, use of the term “an embodiment” or “one embodiment” or“an implementation” or “one implementation” throughout is not intendedto mean the same embodiment or implementation unless described as such.Also, the terms “first,” “second,” “third,” “fourth,” and so forth asused herein are meant as labels to distinguish among different elementsand may not necessarily have an ordinal meaning according to theirnumerical designation.

The invention claimed is:
 1. A device, comprising: a flexible bandconfigured to be worn on a body part of a user, wherein: the flexibleband is configured to extend at least partially around the body part;and the body part comprises a blood vessel disposed within the bodypart; a housing coupled to the flexible band; a processing unitintegrated into the flexible band or disposed within the housing, theprocessing unit comprising: a processing device; or a memory device; auser interface integrated into the flexible band or disposed within thehousing, wherein the user interface is configured to: receive input fromthe user; receive outputs from the processing unit; and display theoutputs; a miniaturized impedance sensor integrated into the flexibleband and positioned at a location along the flexible band that isadjacent to a region of the body part where the blood vessel is closestto an outer surface of the body part when the user wears the device,wherein the miniaturized impedance sensor is configured to: take ameasurement from the blood vessel; and communicate the measurement tothe processing unit, wherein the miniaturized impedance sensorcomprises: an electrode strip having a length greater than a width andthickness of the electrode strip, the electrode strip being oriented onthe flexible band to be parallel to the blood vessel along the length ofthe electrode strip, wherein the electrode strip comprises: parallelrows of electrode dots extending along the length of the electrodestrip, wherein each electrode dot in the rows of electrode dots extendsfrom an inside surface of the flexible band towards the body part whenthe user wears the device and presses into the body part when the userwears the device, and an interstitial filler forming a continuoussurface between the rows of electrode dots, wherein:  the continuoussurface of the interstitial filler is curved between a top surface of atleast one of the parallel rows of electrode dots to allow contactbetween the top surface and the user's skin;  the interstitial filler isabsent from the top surface of the at least one of the parallel rows ofelectrode dots; and  the interstitial filler forms a continuous surfacearound the top surface of the at least one of the parallel rows ofelectrode dots and with the inside surface of the flexible band; and anelectrical trace integrated into the flexible band and configured toelectrically interconnect the processing unit, the user interface, orthe miniaturized impedance sensor.
 2. The device of claim 1, theelectrode strip comprising: a first microelectrode configured totransmit a signal into the body part; and a second microelectrodeconfigured to receive the signal from the body part, wherein the signalpasses through the blood vessel.
 3. The device of claim 2, wherein theelectrode strip further comprises: a third microelectrode positionedbetween the first microelectrode and the second microelectrode; and afourth microelectrode positioned between the first microelectrode andthe second microelectrode, wherein: the miniaturized impedance sensormeasures a voltage between the third microelectrode and the fourthmicroelectrode; and the voltage corresponds to an impedance of the bodypart, the blood vessel, or a material within the blood vessel.
 4. Thedevice of claim 1, wherein: the miniaturized impedance sensor has alength ranging from 2 mm to 10 mm; the miniaturized impedance sensor hasa width ranging from 50 microns to 2 mm; or the miniaturized impedancesensor has a height ranging from 200 microns to 1000 microns.
 5. Thedevice of claim 1, wherein the electrode strip comprises acarbon-infiltrated carbon nanotube forest, wherein thecarbon-infiltrated carbon nanotube forest comprises a bundle of alignedcarbon nanotubes.
 6. The device of claim 1, wherein: the electrode dotcomprises a dot surface configured to form contact with the body part;the dot surface comprises approximately equal length and widthdimensions; the electrode strip comprises a strip surface configured toform contact with the body part; and the strip surface comprises alength dimension of the strip surface that is greater than a widthdimension of the strip surface.
 7. The device of claim 1, wherein, asthe user wears the device, the flexible band extends around the bodypart parallel to a diameter of the blood vessel, and wherein: theminiaturized impedance sensor is aligned to transmit a signal throughthe body part parallel to the diameter of the blood vessel; or theminiaturized impedance sensor is aligned to transmit the signal throughthe body part perpendicular to the diameter of the blood vessel.
 8. Thedevice of claim 1, wherein the miniaturized impedance sensor ispositioned in a region of the flexible band opposite the user interfacewhen the user wears the device.
 9. The device of claim 1, wherein: thebody part comprises a wrist of the user; the miniaturized impedancesensor is positioned against an inside region of the wrist when the userwears the device; and the inside region of the wrist faces towards theuser in a natural resting position.
 10. The device of claim 1 whereinthe interstitial filler includes a first top surface that forms a wellthat dips from a first horizontal plane down to a second horizontalplane and the electrode strip includes a second top surface, wherein thesecond top surface is flush with the first horizontal plane; and an edgeof the first top surface of the interstitial filler is flush with anedge of the second top surface of the electrode strip.
 11. An apparatus,comprising: a miniaturized impedance sensor: integrated into a flexibleband; and positioned at a location along the flexible band to beadjacent to a region of a body part of a user where a blood vessel isclosest to an outer surface of the body part when the user wears theapparatus, wherein the miniaturized impedance sensor: is configured totake a measurement from the blood vessel; and comprises an array ofmicroelectrodes, the array of microelectrodes having a length greaterthan a width and thickness of the electrode and comprising: parallelrows of electrode dots extending along the length of the array, whereineach electrode dot in the rows of electrode dots extends from an insidesurface of the flexible band towards the body part when the user wearsthe apparatus and presses into the body part when the user wears theapparatus, and an interstitial filler forming a continuous surfacebetween the rows of electrode dots wherein the interstitial filler isabsent from the top surface of the at least one of the parallel rows ofelectrode dots; and an electrical trace: integrated into the flexibleband; and configured to electrically interconnect a processing unit, auser interface, or the miniaturized impedance sensor.
 12. The apparatusof claim 11, wherein the miniaturized impedance sensor has a volumeranging from 0.01 cubic millimeters to 20 cubic millimeters.
 13. Theapparatus of claim 11, wherein taking the measurement comprises:transmitting an electric current through the body part; measuring avoltage through the body part corresponding to the electric current; anddetermining an impedance of the body part based on the electric currentor the voltage.
 14. The apparatus of claim 11, wherein: the body partcomprises a vein or an artery; the vein or artery is positioned adjacentto a dermal layer of the body part; a distance between the vein orartery and the miniaturized impedance sensor is less than or equal to athickness of the dermal layer of the body part; and the measurement isindicative of a blood constituent within the vein or the artery.
 15. Adevice, comprising: a miniaturized impedance sensor: integrated into aband; and positioned at a location along the band that is adjacent to aregion of a body part of a user where a structure or a subsurfaceelement is closest to an outer surface of the body part when the userwears the device, wherein the miniaturized impedance sensor: isconfigured to take a measurement from the structure or the subsurfaceelement; and comprises an array of microelectrodes, the array ofmicroelectrodes having a length greater than a width and thickness andcomprising: parallel rows of electrode dots extending along the lengthof the array, wherein each electrode dot in the rows of electrode dotsextends from an inside surface of the flexible band towards the bodypart when the user wears the device, and an interstitial filler forminga continuous surface between the rows of electrode dots wherein theinterstitial filler forms a continuous surface around the top surface ofthe at least one of the parallel rows of electrode dots and with theinside surface of the flexible band; and the interstitial filler iscontinuous with a top surface of the at least one of the parallel rowsof electrode dots, wherein the top surface contacts the body part as theuser wears the device.
 16. The device of claim 15, further comprising anelectrical trace: integrated into the band; and configured toelectrically interconnect a processing unit, a user interface, or theminiaturized impedance sensor.
 17. The device of claim 15, wherein: thestructure or the subsurface element is configured to impede an electriccurrent; and an amount of impedance of the electric current correspondsto a feature of the structure or the subsurface element.
 18. The deviceof claim 15, wherein: the structure comprises a dynamic internal featurewhich cause a variability in an impedance of the structure; and thedynamic internal feature comprises a variable volume or materialconstituency.
 19. The device of claim 15, wherein: the structurecomprises a wrist of a human body; the subsurface element comprises avein or an artery; or the region of the structure directly adjacent tothe subsurface element comprises skin.
 20. The device of claim 15,wherein the miniaturized impedance sensor has a volume ranging from 0.01cubic millimeters to 20 cubic millimeters.